Permit null object in `GenTreeUseEdgeIterator`
Permit null object in `GenTreeUseEdgeIterator`

We use `GT_FIELD` for static field loads, which have no instance pointer.
Update the iterator constructor to recognize this as a valid state rather
than fail an assertion.

botaberg/coreclr,cshung/coreclr,sagood/coreclr,JonHanna/coreclr,dpodder/coreclr,mmitche/coreclr,kyulee1/coreclr,qiudesong/coreclr,alexperovich/coreclr,tijoytom/coreclr,YongseopKim/coreclr,pgavlin/coreclr,ragmani/coreclr,russellhadley/coreclr,kyulee1/coreclr,JosephTremoulet/coreclr,wtgodbe/coreclr,gkhanna79/coreclr,pgavlin/coreclr,yizhang82/coreclr,cydhaselton/coreclr,cshung/coreclr,sagood/coreclr,James-Ko/coreclr,AlexGhiondea/coreclr,tijoytom/coreclr,krytarowski/coreclr,qiudesong/coreclr,rartemev/coreclr,cmckinsey/coreclr,gkhanna79/coreclr,wateret/coreclr,AlexGhiondea/coreclr,mskvortsov/coreclr,tijoytom/coreclr,gkhanna79/coreclr,alexperovich/coreclr,yeaicc/coreclr,JosephTremoulet/coreclr,parjong/coreclr,russellhadley/coreclr,cydhaselton/coreclr,cmckinsey/coreclr,alexperovich/coreclr,James-Ko/coreclr,ruben-ayrapetyan/coreclr,cshung/coreclr,JonHanna/coreclr,ragmani/coreclr,sagood/coreclr,poizan42/coreclr,yeaicc/coreclr,AlexGhiondea/coreclr,qiudesong/coreclr,JonHanna/coreclr,alexperovich/coreclr,dpodder/coreclr,hseok-oh/coreclr,sagood/coreclr,gkhanna79/coreclr,poizan42/coreclr,cmckinsey/coreclr,James-Ko/coreclr,krk/coreclr,pgavlin/coreclr,jamesqo/coreclr,James-Ko/coreclr,botaberg/coreclr,hseok-oh/coreclr,yizhang82/coreclr,cydhaselton/coreclr,JonHanna/coreclr,qiudesong/coreclr,wateret/coreclr,cshung/coreclr,sagood/coreclr,parjong/coreclr,wateret/coreclr,dpodder/coreclr,rartemev/coreclr,mmitche/coreclr,jamesqo/coreclr,wateret/coreclr,ruben-ayrapetyan/coreclr,krk/coreclr,cmckinsey/coreclr,parjong/coreclr,mmitche/coreclr,krk/coreclr,alexperovich/coreclr,hseok-oh/coreclr,rartemev/coreclr,russellhadley/coreclr,jamesqo/coreclr,hseok-oh/coreclr,James-Ko/coreclr,krytarowski/coreclr,tijoytom/coreclr,yeaicc/coreclr,qiudesong/coreclr,rartemev/coreclr,ragmani/coreclr,kyulee1/coreclr,mskvortsov/coreclr,russellhadley/coreclr,YongseopKim/coreclr,mskvortsov/coreclr,YongseopKim/coreclr,cmckinsey/coreclr,AlexGhiondea/coreclr,YongseopKim/coreclr,dpodder/coreclr,cshung/coreclr,mmitche/coreclr,kyulee1/coreclr,gkhanna79/coreclr,wateret/coreclr,qiudesong/coreclr,wtgodbe/coreclr,ragmani/coreclr,ruben-ayrapetyan/coreclr,mmitche/coreclr,cmckinsey/coreclr,botaberg/coreclr,ragmani/coreclr,JosephTremoulet/coreclr,yeaicc/coreclr,yeaicc/coreclr,parjong/coreclr,wateret/coreclr,kyulee1/coreclr,jamesqo/coreclr,krk/coreclr,JonHanna/coreclr,hseok-oh/coreclr,yizhang82/coreclr,krytarowski/coreclr,wtgodbe/coreclr,pgavlin/coreclr,JosephTremoulet/coreclr,rartemev/coreclr,russellhadley/coreclr,James-Ko/coreclr,YongseopKim/coreclr,ruben-ayrapetyan/coreclr,JosephTremoulet/coreclr,parjong/coreclr,yizhang82/coreclr,ruben-ayrapetyan/coreclr,AlexGhiondea/coreclr,yeaicc/coreclr,wtgodbe/coreclr,dpodder/coreclr,YongseopKim/coreclr,botaberg/coreclr,pgavlin/coreclr,krytarowski/coreclr,JonHanna/coreclr,wtgodbe/coreclr,cydhaselton/coreclr,pgavlin/coreclr,mmitche/coreclr,cshung/coreclr,krk/coreclr,gkhanna79/coreclr,krk/coreclr,cmckinsey/coreclr,tijoytom/coreclr,poizan42/coreclr,botaberg/coreclr,ragmani/coreclr,botaberg/coreclr,krytarowski/coreclr,mskvortsov/coreclr,ruben-ayrapetyan/coreclr,hseok-oh/coreclr,dpodder/coreclr,russellhadley/coreclr,cydhaselton/coreclr,poizan42/coreclr,jamesqo/coreclr,poizan42/coreclr,rartemev/coreclr,jamesqo/coreclr,cydhaselton/coreclr,alexperovich/coreclr,yeaicc/coreclr,krytarowski/coreclr,yizhang82/coreclr,mskvortsov/coreclr,wtgodbe/coreclr,mskvortsov/coreclr,poizan42/coreclr,JosephTremoulet/coreclr,parjong/coreclr,AlexGhiondea/coreclr,tijoytom/coreclr,kyulee1/coreclr,sagood/coreclr,yizhang82/coreclr