BENCH: Add pyarrow to env
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [ ] whatsnew entry

This came up while I was benchmarking the pyarrow csv reader that I am planning to PR soon, which was erroring with an ImportError for pyarrow. Anyone know if this is the right patch? (It works correctly for me afterwards, however I am curious as to how ArrowStringArray was getting benchmarked)

pytest also should be removable I think. (there really shouldn't be any reason why we are benchmarking that)
cc @simonjayhawkins @TomAugspurger 
lgtm thanks @lithomas1 

yeah this should also help with the string functions, we *should* have the parameterizations already. cc @simonjayhawkins 