[PATCH] [X86] Add patterns for AVX2 VPMOV[SZ]XYrm intrinsics.

[Elena Demikhovsky]

I'd add these intrinsics to X86IntrinsicsInfo.h in the following form:
X86_INTRINSIC_DATA(avx2_pmovsxbq,   INTR_TYPE_1OP, X86ISD::VSEXT, 0).
We try to use this way instead adding patterns.

Please add Adam Nemet to reviewers.

http://reviews.llvm.org/D6125