TST: incorrect localization in append testing
TST: incorrect localization in append testing

and when ``pytz`` version changes our tests break because of this
incorrect (old) method, which works when you *dont'* have a tz change,
but fails when the tz's actually change.

Author: Jeff Reback <jeff@reback.net>

Closes #15849 from jreback/localize and squashes the following commits:

d43d088 [Jeff Reback] TST: incorrect localization in append testing

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