AVX-512: Added more intrinsics for convert and min/max.
Removed vzeroupper from AVX-512 mode - our optimization gude does not recommend to insert vzeroupper at all.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198557 91177308-0d34-0410-b5e6-96231b3b80d8