[X86] Don't do anything in ReplaceNodeResults for (v2i32 (fptoui/fptosi...

[X86] Don't do anything in ReplaceNodeResults for (v2i32 (fptoui/fptosi v2f32)) when -x86-experimental-vector-widening-legalization is on.

We don't need to do our own widening, the generic legalizer can do it.

llvm-svn: 341174