[X86] Use i8 immediate for comparison type on AVX512 packed integer instructions. This matches floating point equivalents. Includes autoupgrade support to convert old code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227063 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed