[X86] Auto upgrade XOP/AVX512 rotation intrinsics to generic funnel shift intrinsics (clang)

This emits FSHL/FSHR generic intrinsics for the XOP VPROT and AVX512 VPROL/VPROR rotation intrinsics.

LLVM counterpart: https://reviews.llvm.org/D55938

Differential Revision: https://reviews.llvm.org/D55937

llvm-svn: 349796