[llvm] [X86] Recognize VPXORDZrr as a zero-idiom on Znver4 (PR #108314)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

I don't have hardware to test that this is actually a zero-idiom, but I would definitely expect it to be.

This is just a stop-gap for the linked issue. Once we have confirmation on the other AVX512 zero-idioms for `znver4`, we should add those in too as a follow-up step.

https://github.com/llvm/llvm-project/pull/108314