[X86] Allow combineVectorCompareAndMaskUnaryOp to handle 'all-bits' general case

For the sint_to_fp(and(X,C)) -> and(X,sint_to_fp(C)) fold, allow combineVectorCompareAndMaskUnaryOp to match any X that ComputeNumSignBits says is all-bits, not just SETCC.

Noticed while investigating mask promotion issues in PR45808