CLN: ASV series_methods
Utilized `param` and cleaned up some benchmarks.

```
asv dev -b ^series_methods
· Discovering benchmarks
· Running 9 total benchmarks (1 commits * 1 environments * 9 benchmarks)
[  0.00%] ·· Building for existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[  0.00%] ·· Benchmarking existing-py_home_matt_anaconda_envs_pandas_dev_bin_python
[ 11.11%] ··· Running series_methods.Clip.time_clip                       290μs
[ 22.22%] ··· Running series_methods.Dir.time_dir_strings                30.5ms
[ 33.33%] ··· Running series_methods.Dropna.time_dropna                      ok
[ 33.33%] ···· 
               ========== ========
                 dtype            
               ---------- --------
                  int      4.20ms 
                datetime   19.4ms 
               ========== ========

[ 44.44%] ··· Running series_methods.IsIn.time_isin                          ok
[ 44.44%] ···· 
               ======== ========
                dtype           
               -------- --------
                int64    2.63ms 
                object   5.03ms 
               ======== ========

[ 55.56%] ··· Running series_methods.Map.time_map                            ok
[ 55.56%] ···· 
               ======== ========
                  m             
               -------- --------
                 dict    3.54ms 
                Series   2.31ms 
               ======== ========

[ 66.67%] ··· Running series_methods.NSort.time_nlargest                     ok
[ 66.67%] ···· 
               ======= ========
                 keep          
               ------- --------
                 last   5.20ms 
                first   5.53ms 
               ======= ========

[ 77.78%] ··· Running series_methods.NSort.time_nsmallest                    ok
[ 77.78%] ···· 
               ======= ========
                 keep          
               ------- --------
                 last   4.19ms 
                first   5.00ms 
               ======= ========

[ 88.89%] ··· Running ..._methods.SeriesConstructor.time_constructor         ok
[ 88.89%] ···· 
               ====== =======
                data         
               ------ -------
                None   726μs 
                dict   1.56s 
               ====== =======

[100.00%] ··· Running series_methods.ValueCounts.time_value_counts           ok
[100.00%] ···· 
               ======== ========
                dtype           
               -------- --------
                 int     4.63ms 
                float    7.00ms 
                object   24.7ms 
               ======== ========
```

thanks @mroeschke 

getting close to full ability to lint check asvs looks like! Yup! Two more files until we can start linting asvs. 