[clang] [llvm] Try to use non-volatile registers for `preserve_none` parameters (PR #88333)

[Brandt Bucher via llvm-commits]

brandtbucher wrote:

The Windows x64 Buildkite CI job is failing, but I can't find any failed tests in the downloaded logs. Any advice? 

https://github.com/llvm/llvm-project/pull/88333