[llvm] [X86][NFC] Reorder the registers to reduce unnecessary iterations (PR #70222)

[Phoebe Wang via llvm-commits]

https://github.com/phoebewang approved this pull request.

I don't see objections to this patch, so I'll approve to unblock our follow up patches.
I think as a workaround, this patch solves the compiler time regression caused by adding new registers. We can remove it once we don't need LIveVariables.

https://github.com/llvm/llvm-project/pull/70222