PERF: Benchmark merge with non-int64 and tolerance (#28922)
- [X] closes #28922
- [ ] tests added / passed
- [X] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
Currently implements a parameterized tolerance benchmark using `tolerance=None` and `tolerance=5000`. I've run the ASV using different values (*5, 100, 5000, 10000*) without noticable changes in the results. Therefore I've opted for the current arbitrary value of 5000.

Results of these benchmarks:
`tolerance=5`:
<details>

· Discovering benchmarks
· Running 6 total benchmarks (1 commits * 1 environments * 6 benchmarks)
[  0.00%] ·· Benchmarking existing-pyc__users_jjlkant_anaconda3_envs_pandas-dev_python.exe
[  8.33%] ··· Running (join_merge.MergeAsof.time_by_int--).
[ 16.67%] ··· Running (join_merge.MergeAsof.time_by_object--).
[ 25.00%] ··· Running (join_merge.MergeAsof.time_multiby--).
[ 33.33%] ··· Running (join_merge.MergeAsof.time_on_int--)..
[ 50.00%] ··· Running (join_merge.MergeAsof.time_on_uint64--).
[ 58.33%] ··· join_merge.MergeAsof.time_by_int                                                                                                                                                                                            ok
[ 58.33%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None        5
              =========== ========== ==========
                backward   96.4±9ms   100±20ms
                forward    192±10ms   170±10ms
                nearest    219±10ms   266±30ms
              =========== ========== ==========

[ 66.67%] ··· join_merge.MergeAsof.time_by_object                                                                                                                                                                                         ok
[ 66.67%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None        5
              =========== ========== ==========
                backward   95.8±5ms   104±10ms
                forward    177±30ms   201±50ms
                nearest    288±30ms   280±30ms
              =========== ========== ==========

[ 75.00%] ··· join_merge.MergeAsof.time_multiby                                                                                                                                                                                           ok
[ 75.00%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None        5
              =========== ========== ==========
                backward   706±30ms   663±60ms
                forward    769±20ms   735±5ms
                nearest    822±10ms   823±10ms
              =========== ========== ==========

[ 83.33%] ··· join_merge.MergeAsof.time_on_int                                                                                                                                                                                            ok
[ 83.33%] ··· =========== ========== ===========
              --                tolerance
              ----------- ----------------------
               direction     None         5
              =========== ========== ===========
                backward   29.3±3ms    29.5±1ms
                forward    35.4±5ms    34.5±6ms
                nearest    47.8±7ms   46.0±10ms
              =========== ========== ===========

[ 91.67%] ··· join_merge.MergeAsof.time_on_int32                                                                                                                                                                                          ok
[ 91.67%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None        5
              =========== ========== ==========
                backward   35.7±6ms   35.0±4ms
                forward    41.2±9ms   35.3±3ms
                nearest    42.9±6ms   51.3±5ms
              =========== ========== ==========

[100.00%] ··· join_merge.MergeAsof.time_on_uint64                                                                                                                                                                                         ok
[100.00%] ··· =========== =========== ==========
              --                tolerance
              ----------- ----------------------
               direction      None        5
              =========== =========== ==========
                backward    35.5±7ms   36.5±5ms
                forward     45.0±3ms   40.4±8ms
                nearest    44.1±10ms   51.9±7ms
              =========== =========== ==========

</details>

`tolerance=100` and `tolerance=10000`:
<details>

· Discovering benchmarks
· Running 6 total benchmarks (1 commits * 1 environments * 6 benchmarks)
[  0.00%] ·· Benchmarking existing-pyc__users_jjlkant_anaconda3_envs_pandas-dev_python.exe
[  8.33%] ··· Running (join_merge.MergeAsof.time_by_int--).
[ 16.67%] ··· Running (join_merge.MergeAsof.time_by_object--).
[ 25.00%] ··· Running (join_merge.MergeAsof.time_multiby--).
[ 33.33%] ··· Running (join_merge.MergeAsof.time_on_int--).
[ 41.67%] ··· Running (join_merge.MergeAsof.time_on_int32--).
[ 50.00%] ··· Running (join_merge.MergeAsof.time_on_uint64--).
[ 58.33%] ··· join_merge.MergeAsof.time_by_int                                                                                                                                                                                            ok
[ 58.33%] ··· =========== =========== ========== ==========
              --                      tolerance
              ----------- ---------------------------------
               direction      None       100       10000
              =========== =========== ========== ==========
                backward   99.9±30ms   108±10ms   102±6ms
                forward     163±30ms   171±10ms   173±20ms
                nearest     238±10ms   236±20ms   233±10ms
              =========== =========== ========== ==========

[ 66.67%] ··· join_merge.MergeAsof.time_by_object                                                                                                                                                                                         ok
[ 66.67%] ··· =========== ========== ========== ==========
              --                     tolerance
              ----------- --------------------------------
               direction     None       100       10000
              =========== ========== ========== ==========
                backward   105±10ms   94.8±7ms   95.8±4ms
                forward    188±8ms    172±9ms    191±30ms
                nearest    238±10ms   246±8ms    242±20ms
              =========== ========== ========== ==========

[ 75.00%] ··· join_merge.MergeAsof.time_multiby                                                                                                                                                                                           ok
[ 75.00%] ··· =========== ========== ========== ==========
              --                     tolerance
              ----------- --------------------------------
               direction     None       100       10000
              =========== ========== ========== ==========
                backward   653±20ms   661±20ms   662±10ms
                forward    751±10ms   763±20ms   775±8ms
                nearest    849±30ms   851±50ms   861±30ms
              =========== ========== ========== ==========

[ 83.33%] ··· join_merge.MergeAsof.time_on_int                                                                                                                                                                                            ok
[ 83.33%] ··· =========== ========== ========== ==========
              --                     tolerance
              ----------- --------------------------------
               direction     None       100       10000
              =========== ========== ========== ==========
                backward   32.0±4ms   31.5±5ms   30.3±2ms
                forward    34.1±4ms   35.1±6ms   32.9±1ms
                nearest    41.7±6ms   43.4±6ms   43.3±3ms
              =========== ========== ========== ==========

[ 91.67%] ··· join_merge.MergeAsof.time_on_int32                                                                                                                                                                                          ok
[ 91.67%] ··· =========== ========== ========== ==========
              --                     tolerance
              ----------- --------------------------------
               direction     None       100       10000
              =========== ========== ========== ==========
                backward   35.1±3ms   36.2±3ms   40.2±4ms
                forward    34.5±4ms   36.4±1ms   34.8±3ms
                nearest    39.5±3ms   39.5±4ms   49.3±8ms
              =========== ========== ========== ==========

[100.00%] ··· join_merge.MergeAsof.time_on_uint64                                                                                                                                                                                         ok
[100.00%] ··· =========== ============ ========== ===========
              --                       tolerance
              ----------- -----------------------------------
               direction      None        100        10000
              =========== ============ ========== ===========
                backward   30.4±0.8ms   32.3±5ms    28.6±4ms
                forward     31.7±4ms    33.0±2ms    34.8±4ms
                nearest     39.8±4ms    44.6±4ms   48.1±10ms
              =========== ============ ========== ===========

</details>

`tolerance=5000`:
<details>

· Discovering benchmarks
· Running 6 total benchmarks (1 commits * 1 environments * 6 benchmarks)
[  0.00%] ·· Benchmarking existing-pyc__users_jjlkant_anaconda3_envs_pandas-dev_python.exe
[  8.33%] ··· Running (join_merge.MergeAsof.time_by_int--)..
[ 25.00%] ··· Running (join_merge.MergeAsof.time_multiby--).
[ 33.33%] ··· Running (join_merge.MergeAsof.time_on_int--)..
[ 50.00%] ··· Running (join_merge.MergeAsof.time_on_uint64--).
[ 58.33%] ··· join_merge.MergeAsof.time_by_int                                                                                                                                                                                            ok
[ 58.33%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   104±20ms   111±20ms
                forward    217±50ms   207±60ms
                nearest    287±60ms   290±50ms
              =========== ========== ==========

[ 66.67%] ··· join_merge.MergeAsof.time_by_object                                                                                                                                                                                         ok
[ 66.67%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   124±20ms   142±30ms
                forward    209±20ms   203±10ms
                nearest    274±10ms   276±10ms
              =========== ========== ==========

[ 75.00%] ··· join_merge.MergeAsof.time_multiby                                                                                                                                                                                           ok
[ 75.00%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   667±20ms   687±40ms
                forward    799±40ms   775±30ms
                nearest    836±10ms   845±30ms
              =========== ========== ==========

[ 83.33%] ··· join_merge.MergeAsof.time_on_int                                                                                                                                                                                            ok
[ 83.33%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   32.3±5ms   31.1±2ms
                forward    30.9±3ms   30.6±2ms
                nearest    38.7±2ms   40.0±3ms
              =========== ========== ==========

[ 91.67%] ··· join_merge.MergeAsof.time_on_int32                                                                                                                                                                                          ok
[ 91.67%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   30.8±4ms   31.7±5ms
                forward    45.6±8ms   40.2±5ms
                nearest    43.4±2ms   47.6±7ms
              =========== ========== ==========

[100.00%] ··· join_merge.MergeAsof.time_on_uint64                                                                                                                                                                                         ok
[100.00%] ··· =========== ========== ==========
              --                tolerance
              ----------- ---------------------
               direction     None       5000
              =========== ========== ==========
                backward   36.8±5ms   43.5±5ms
                forward    34.7±5ms   40.1±5ms
                nearest    39.3±2ms   43.9±7ms
              =========== ========== ==========

</details> Thanks @jjlkant !