[X86][SSE] Replace (V)PMOVSX and (V)PMOVZX integer extension intrinsics with generic IR (llvm)

This patch removes the llvm intrinsics VPMOVSX and (V)PMOVZX sign/zero extension intrinsics and auto-upgrades to SEXT/ZEXT calls instead. We already did this for SSE41 PMOVSX sometime ago so much of that implementation can be reused.

A companion patch (D20684) removes/auto-upgrade the clang intrinsics.

Differential Revision: http://reviews.llvm.org/D20686

llvm-svn: 270973