[clang] [llvm] [X86] Support reserving EDI and ESI on x86-32 (PR #186123)

[Phoebe Wang via cfe-commits]

phoebewang wrote:

I think @efriedma-quic was opposited the 32-bit support. I'm inclined to not do it unless there's claer requirment.

https://github.com/llvm/llvm-project/pull/186123