[AVX512] Removed special case for cmp instructions in getVectorMaskingNode. Now cmp intrinsics lower as other intrinsics through VSELECT, and then VSELECT tranforms to AND in PerformSELECTCombine.
No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220779 91177308-0d34-0410-b5e6-96231b3b80d8