Always use XORPS/ANDPS for FP NEG/ABS
Always use XORPS/ANDPS for FP NEG/ABS

They do the same thing but they're one byte shorter. Saves a call to genGetInsForOper too.

JosephTremoulet/coreclr,cshung/coreclr,poizan42/coreclr,poizan42/coreclr,wtgodbe/coreclr,JosephTremoulet/coreclr,JosephTremoulet/coreclr,mmitche/coreclr,krk/coreclr,ruben-ayrapetyan/coreclr,yizhang82/coreclr,krk/coreclr,wtgodbe/coreclr,krk/coreclr,cshung/coreclr,wtgodbe/coreclr,mmitche/coreclr,yizhang82/coreclr,yizhang82/coreclr,JosephTremoulet/coreclr,ruben-ayrapetyan/coreclr,JosephTremoulet/coreclr,krk/coreclr,ruben-ayrapetyan/coreclr,krk/coreclr,yizhang82/coreclr,yizhang82/coreclr,wateret/coreclr,poizan42/coreclr,wtgodbe/coreclr,cshung/coreclr,poizan42/coreclr,mmitche/coreclr,mmitche/coreclr,poizan42/coreclr,wtgodbe/coreclr,krk/coreclr,JosephTremoulet/coreclr,wateret/coreclr,wateret/coreclr,wateret/coreclr,ruben-ayrapetyan/coreclr,wtgodbe/coreclr,ruben-ayrapetyan/coreclr,mmitche/coreclr,ruben-ayrapetyan/coreclr,cshung/coreclr,cshung/coreclr,cshung/coreclr,poizan42/coreclr,wateret/coreclr,mmitche/coreclr,yizhang82/coreclr,wateret/coreclr