[X86] Rewrite avx512vbmi unmasked and maskz macro intrinsics to be wrappers...

[X86] Rewrite avx512vbmi unmasked and maskz macro intrinsics to be wrappers around their __builtin function with appropriate arguments rather than just passing arguments to the masked intrinsic.

This is more consistent with all of our other avx512 macro intrinsics.

It also fixes a bad cast where an argument was casted to mmask8 when it should have been a mmask16.

llvm-svn: 333778