[clang] [llvm] [X86][Driver] Do not add `-evex512` for `-march=native` when the target doesn't support AVX512 (PR #91694)

[Phoebe Wang via cfe-commits]

phoebewang wrote:

> You'll be probably building 18.1.6 with 18.1.5... and that's when you'll notice the issue. I'm just about finished building 18.1.5 with your patch. So hopefully all those issues will be gone. I'll report back

Okay... This is a combined problem which I never thought before. Sorry for the inconvenience!

https://github.com/llvm/llvm-project/pull/91694