REF: Convert test_hashing to pytest idiom (#24009)
REF: Convert test_hashing to pytest idiom (#24009)

Also patch bug in the tests as follows:

_check_equal appeared to be checking index=True/False,
but we actually need to do explicitly pass in
index=True/False for this to work.

dsm054/pandas,gfyoung/pandas,gfyoung/pandas,pandas-dev/pandas,jreback/pandas,GuessWhoSamFoo/pandas,TomAugspurger/pandas,jreback/pandas,gfyoung/pandas,rs2/pandas,GuessWhoSamFoo/pandas,toobaz/pandas,datapythonista/pandas,jreback/pandas,jorisvandenbossche/pandas,MJuddBooth/pandas,jorisvandenbossche/pandas,cbertinato/pandas,datapythonista/pandas,gfyoung/pandas,datapythonista/pandas,jreback/pandas,MJuddBooth/pandas,gfyoung/pandas,dsm054/pandas,GuessWhoSamFoo/pandas,rs2/pandas,rs2/pandas,dsm054/pandas,jreback/pandas,MJuddBooth/pandas,rs2/pandas,dsm054/pandas,pandas-dev/pandas,toobaz/pandas,cbertinato/pandas,toobaz/pandas,jorisvandenbossche/pandas,pandas-dev/pandas,TomAugspurger/pandas,cbertinato/pandas,MJuddBooth/pandas,jorisvandenbossche/pandas,toobaz/pandas,TomAugspurger/pandas,GuessWhoSamFoo/pandas,cbertinato/pandas,TomAugspurger/pandas,GuessWhoSamFoo/pandas,toobaz/pandas,MJuddBooth/pandas,datapythonista/pandas,pandas-dev/pandas,cbertinato/pandas,dsm054/pandas