STYLE: Fix linting of benchmarks
- [x] closes #22884 
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Fixed the following:

` asv_bench/benchmarks/algorithms.py:12:5: E722 do not use bare except'
asv_bench/benchmarks/timeseries.py:1:1: F401 'warnings' imported but unused
asv_bench/benchmarks/stat_ops.py:21:9: E722 do not use bare except'
asv_bench/benchmarks/stat_ops.py:59:9: E722 do not use bare except'
asv_bench/benchmarks/pandas_vb_common.py:5:1: F401 'pandas.Panel' imported but unused
asv_bench/benchmarks/pandas_vb_common.py:12:5: E722 do not use bare except'
asv_bench/benchmarks/pandas_vb_common.py:37:9: E722 do not use bare except'
asv_bench/benchmarks/join_merge.py:32:9: E722 do not use bare except'
asv_bench/benchmarks/io/csv.py:2:1: F401 'timeit' imported but unused
asv_bench/benchmarks/io/csv.py:8:1: F401 'pandas.compat.PY2' imported but unused
asv_bench/benchmarks/io/csv.py:184:80: E501 line too long (87 > 79 characters)  `
Hello @MatanCohe! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/algorithms.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/algorithms.py) !

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/io/csv.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/io/csv.py) !

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/join_merge.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/join_merge.py) !

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/pandas_vb_common.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/pandas_vb_common.py) !

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/stat_ops.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/stat_ops.py) !

 - There are no PEP8 issues in the file [`asv_bench/benchmarks/timeseries.py`](https://github.com/MatanCohe/pandas/blob/9b1cfb28591b52956a25cd0494f3b5450290a874/asv_bench/benchmarks/timeseries.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=h1) Report
> Merging [#22886](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e45a6c14fc969c31c46ae890e72883ffe6658b4e?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22886/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22886   +/-   ##
=======================================
  Coverage   92.18%   92.18%           
=======================================
  Files         169      169           
  Lines       50830    50830           
=======================================
  Hits        46860    46860           
  Misses       3970     3970
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.6% <ø> (ø)` | :arrow_up: |
| #single | `42.37% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=footer). Last update [e45a6c1...9b1cfb2](https://codecov.io/gh/pandas-dev/pandas/pull/22886?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @MatanCohe : Awesome work.  Thanks!