[clang] [compiler-rt] [llvm] [X86] Support -march=diamondrapids (PR #113881)

[Nico Weber via cfe-commits]

nico wrote:

Looks like this breaks tests: http://45.33.8.238/linux/153081/step_6.txt

Please take a look and revert for now if it takes a while to fix.

https://github.com/llvm/llvm-project/pull/113881