Add tests for Array.IndexOf (#11716)
Add tests for Array.IndexOf (#11716)

* Cleanup Array.IndexOf tests. Make it easier to add new tests
* Fix Array.Reverse test to test all overloads with non-zero lower bound arrays
* Add tests for Array.IndexOf
dotnet-bot/corefx,JosephTremoulet/corefx,ptoonen/corefx,elijah6/corefx,cydhaselton/corefx,ptoonen/corefx,yizhang82/corefx,fgreinacher/corefx,rubo/corefx,ericstj/corefx,Petermarcu/corefx,ViktorHofer/corefx,tijoytom/corefx,Ermiar/corefx,wtgodbe/corefx,shmao/corefx,Petermarcu/corefx,rahku/corefx,ravimeda/corefx,Ermiar/corefx,mmitche/corefx,richlander/corefx,the-dwyer/corefx,krytarowski/corefx,stone-li/corefx,ViktorHofer/corefx,dotnet-bot/corefx,ravimeda/corefx,rubo/corefx,wtgodbe/corefx,the-dwyer/corefx,krk/corefx,YoupHulsebos/corefx,nchikanov/corefx,zhenlan/corefx,rahku/corefx,richlander/corefx,rjxby/corefx,richlander/corefx,weltkante/corefx,mmitche/corefx,fgreinacher/corefx,ravimeda/corefx,ericstj/corefx,ericstj/corefx,parjong/corefx,richlander/corefx,MaggieTsang/corefx,rahku/corefx,BrennanConroy/corefx,dotnet-bot/corefx,krk/corefx,mazong1123/corefx,rubo/corefx,ptoonen/corefx,ravimeda/corefx,nbarbettini/corefx,elijah6/corefx,alexperovich/corefx,billwert/corefx,Jiayili1/corefx,elijah6/corefx,ravimeda/corefx,rjxby/corefx,cydhaselton/corefx,marksmeltzer/corefx,lggomez/corefx,billwert/corefx,yizhang82/corefx,tijoytom/corefx,weltkante/corefx,ericstj/corefx,krytarowski/corefx,jlin177/corefx,axelheer/corefx,YoupHulsebos/corefx,MaggieTsang/corefx,zhenlan/corefx,marksmeltzer/corefx,Petermarcu/corefx,mmitche/corefx,lggomez/corefx,dhoehna/corefx,zhenlan/corefx,nchikanov/corefx,dotnet-bot/corefx,fgreinacher/corefx,zhenlan/corefx,twsouthwick/corefx,wtgodbe/corefx,MaggieTsang/corefx,ViktorHofer/corefx,cydhaselton/corefx,marksmeltzer/corefx,axelheer/corefx,JosephTremoulet/corefx,rjxby/corefx,billwert/corefx,krk/corefx,seanshpark/corefx,axelheer/corefx,tijoytom/corefx,fgreinacher/corefx,ravimeda/corefx,DnlHarvey/corefx,gkhanna79/corefx,stephenmichaelf/corefx,shmao/corefx,MaggieTsang/corefx,nbarbettini/corefx,ViktorHofer/corefx,nbarbettini/corefx,mazong1123/corefx,rahku/corefx,yizhang82/corefx,shimingsg/corefx,marksmeltzer/corefx,dotnet-bot/corefx,marksmeltzer/corefx,seanshpark/corefx,mmitche/corefx,parjong/corefx,zhenlan/corefx,gkhanna79/corefx,jlin177/corefx,seanshpark/corefx,billwert/corefx,rahku/corefx,Ermiar/corefx,lggomez/corefx,jlin177/corefx,stephenmichaelf/corefx,yizhang82/corefx,Ermiar/corefx,JosephTremoulet/corefx,twsouthwick/corefx,alexperovich/corefx,weltkante/corefx,alexperovich/corefx,rjxby/corefx,DnlHarvey/corefx,twsouthwick/corefx,DnlHarvey/corefx,dhoehna/corefx,stephenmichaelf/corefx,wtgodbe/corefx,krytarowski/corefx,the-dwyer/corefx,ViktorHofer/corefx,jlin177/corefx,yizhang82/corefx,twsouthwick/corefx,krytarowski/corefx,the-dwyer/corefx,alexperovich/corefx,billwert/corefx,DnlHarvey/corefx,shmao/corefx,parjong/corefx,ViktorHofer/corefx,nchikanov/corefx,seanshpark/corefx,stone-li/corefx,alexperovich/corefx,nchikanov/corefx,ptoonen/corefx,MaggieTsang/corefx,stone-li/corefx,krk/corefx,the-dwyer/corefx,dhoehna/corefx,axelheer/corefx,nchikanov/corefx,richlander/corefx,richlander/corefx,YoupHulsebos/corefx,lggomez/corefx,mazong1123/corefx,ViktorHofer/corefx,elijah6/corefx,cydhaselton/corefx,Jiayili1/corefx,cydhaselton/corefx,YoupHulsebos/corefx,Jiayili1/corefx,Petermarcu/corefx,dhoehna/corefx,DnlHarvey/corefx,zhenlan/corefx,tijoytom/corefx,Ermiar/corefx,rjxby/corefx,DnlHarvey/corefx,nbarbettini/corefx,gkhanna79/corefx,YoupHulsebos/corefx,JosephTremoulet/corefx,billwert/corefx,zhenlan/corefx,Jiayili1/corefx,the-dwyer/corefx,tijoytom/corefx,mazong1123/corefx,alexperovich/corefx,stephenmichaelf/corefx,shimingsg/corefx,lggomez/corefx,weltkante/corefx,BrennanConroy/corefx,ptoonen/corefx,axelheer/corefx,tijoytom/corefx,Ermiar/corefx,twsouthwick/corefx,MaggieTsang/corefx,jlin177/corefx,rubo/corefx,parjong/corefx,weltkante/corefx,Ermiar/corefx,stone-li/corefx,stephenmichaelf/corefx,rjxby/corefx,marksmeltzer/corefx,JosephTremoulet/corefx,DnlHarvey/corefx,richlander/corefx,krytarowski/corefx,wtgodbe/corefx,YoupHulsebos/corefx,dhoehna/corefx,krk/corefx,ericstj/corefx,twsouthwick/corefx,cydhaselton/corefx,mazong1123/corefx,yizhang82/corefx,nchikanov/corefx,stephenmichaelf/corefx,elijah6/corefx,nbarbettini/corefx,parjong/corefx,JosephTremoulet/corefx,mazong1123/corefx,ptoonen/corefx,seanshpark/corefx,lggomez/corefx,rjxby/corefx,twsouthwick/corefx,elijah6/corefx,mmitche/corefx,tijoytom/corefx,YoupHulsebos/corefx,shmao/corefx,parjong/corefx,shmao/corefx,cydhaselton/corefx,stone-li/corefx,shimingsg/corefx,wtgodbe/corefx,mazong1123/corefx,elijah6/corefx,the-dwyer/corefx,BrennanConroy/corefx,marksmeltzer/corefx,ravimeda/corefx,seanshpark/corefx,rubo/corefx,shimingsg/corefx,shmao/corefx,MaggieTsang/corefx,krytarowski/corefx,Jiayili1/corefx,ericstj/corefx,dhoehna/corefx,gkhanna79/corefx,jlin177/corefx,Jiayili1/corefx,rahku/corefx,gkhanna79/corefx,weltkante/corefx,shimingsg/corefx,shimingsg/corefx,nbarbettini/corefx,Jiayili1/corefx,stone-li/corefx,weltkante/corefx,shimingsg/corefx,stone-li/corefx,JosephTremoulet/corefx,gkhanna79/corefx,lggomez/corefx,rahku/corefx,mmitche/corefx,Petermarcu/corefx,Petermarcu/corefx,dhoehna/corefx,alexp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