[AVX-512] Remove vextract intrinsics and autoupgrade to native shufflevectors. This unfortunately generates some really terrible code without VLX support due to v2i1 and v4i1 not being legal.

Hopefully we can improve that in future patches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290863 91177308-0d34-0410-b5e6-96231b3b80d8
11 files changed