[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:

> Could you make getHostCPUFeatures only write the Features["evex512"] entry if Features["avx512f"] is true? Instead of copying Features["avx512f"]?

Good idea, done.

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