TST: Fix MMapWrapper init test for Windows
TST: Fix MMapWrapper init test for Windows

Turns out Windows errors differently when an invalid `fileno` is
passed into the `mmap` constructor, so there's no need to skip the
test (xref: 9670b31).

Author: gfyoung <gfyoung17@gmail.com>

Closes #13494 from gfyoung/mmap-wrapper-init-test-fix and squashes the following commits:

db7c6b1 [gfyoung] TST: Fix MMapWrapper init test for Windows

linebp/pandas,jmmease/pandas,kdebrab/pandas,toobaz/pandas,rs2/pandas,MJuddBooth/pandas,zfrenchee/pandas,linebp/pandas,gfyoung/pandas,linebp/pandas,nmartensen/pandas,TomAugspurger/pandas,MJuddBooth/pandas,linebp/pandas,linebp/pandas,pratapvardhan/pandas,GuessWhoSamFoo/pandas,Winand/pandas,pandas-dev/pandas,rs2/pandas,linebp/pandas,pratapvardhan/pandas,gfyoung/pandas,gfyoung/pandas,louispotok/pandas,zfrenchee/pandas,GuessWhoSamFoo/pandas,amolkahat/pandas,rs2/pandas,dsm054/pandas,jreback/pandas,jreback/pandas,pratapvardhan/pandas,Winand/pandas,jorisvandenbossche/pandas,dsm054/pandas,jreback/pandas,GuessWhoSamFoo/pandas,harisbal/pandas,datapythonista/pandas,cbertinato/pandas,jmmease/pandas,zfrenchee/pandas,winklerand/pandas,winklerand/pandas,jmmease/pandas,gfyoung/pandas,Winand/pandas,cbertinato/pandas,louispotok/pandas,louispotok/pandas,TomAugspurger/pandas,DGrady/pandas,datapythonista/pandas,datapythonista/pandas,cython-testbed/pandas,toobaz/pandas,rs2/pandas,toobaz/pandas,jmmease/pandas,amolkahat/pandas,kdebrab/pandas,cbertinato/pandas,jreback/pandas,pratapvardhan/pandas,louispotok/pandas,dsm054/pandas,amolkahat/pandas,Winand/pandas,cython-testbed/pandas,cython-testbed/pandas,harisbal/pandas,GuessWhoSamFoo/pandas,cbertinato/pandas,pandas-dev/pandas,jmmease/pandas,louispotok/pandas,kdebrab/pandas,pandas-dev/pandas,gfyoung/pandas,dsm054/pandas,pandas-dev/pandas,Winand/pandas,jmmease/pandas,harisbal/pandas,winklerand/pandas,jreback/pandas,cython-testbed/pandas,harisbal/pandas,kdebrab/pandas,TomAugspurger/pandas,cbertinato/pandas,jorisvandenbossche/pandas,winklerand/pandas,jorisvandenbossche/pandas,nmartensen/pandas,jorisvandenbossche/pandas,GuessWhoSamFoo/pandas,nmartensen/pandas,TomAugspurger/pandas,nmartensen/pandas,zfrenchee/pandas,DGrady/pandas,DGrady/pandas,DGrady/pandas,amolkahat/pandas,MJuddBooth/pandas,DGrady/pandas,dsm054/pandas,cython-testbed/pandas,DGrady/pandas,nmartensen/pandas,nmartensen/pandas,MJuddBooth/pandas,toobaz/pandas,pratapvardhan/pandas,kdebrab/pandas,harisbal/pandas,amolkahat/pandas,winklerand/pandas,zfrenchee/pandas,Winand/pandas,MJuddBooth/pandas,toobaz/pandas,datapythonista/pandas,winklerand/pandas