Give a proper VN to GT_BOX (#15666)
Give a proper VN to GT_BOX (#15666)

GT_BOX doesn't do anything so it should just get the VN of its sole operand. This allows assertion prop to see that the result of BOX is not null (since the BOX operand is the result of an object allocation which is never null).
JosephTremoulet/coreclr,yizhang82/coreclr,krk/coreclr,yizhang82/coreclr,yizhang82/coreclr,cshung/coreclr,JosephTremoulet/coreclr,JosephTremoulet/coreclr,krk/coreclr,cshung/coreclr,JosephTremoulet/coreclr,JosephTremoulet/coreclr,krk/coreclr,wtgodbe/coreclr,cshung/coreclr,JosephTremoulet/coreclr,ruben-ayrapetyan/coreclr,poizan42/coreclr,mmitche/coreclr,cshung/coreclr,mmitche/coreclr,wtgodbe/coreclr,wtgodbe/coreclr,wtgodbe/coreclr,poizan42/coreclr,krk/coreclr,mmitche/coreclr,wtgodbe/coreclr,yizhang82/coreclr,mmitche/coreclr,yizhang82/coreclr,cshung/coreclr,ruben-ayrapetyan/coreclr,wtgodbe/coreclr,cshung/coreclr,mmitche/coreclr,krk/coreclr,ruben-ayrapetyan/coreclr,poizan42/coreclr,ruben-ayrapetyan/coreclr,poizan42/coreclr,poizan42/coreclr,ruben-ayrapetyan/coreclr,ruben-ayrapetyan/coreclr,mmitche/coreclr,poizan42/coreclr,yizhang82/coreclr,krk/coreclr