[X86][SSE] VSELECT(XOR(Cond,-1), LHS, RHS) --> VSELECT(Cond, RHS, LHS)

As noticed on D58965

DAGCombiner::visitSELECT has something similar, so we should be able to move this to DAGCombiner and support VSELECT as well at some point.

Differential Revision: https://reviews.llvm.org/D58974

llvm-svn: 355494