[clang] [amdgpu] Pass variadic arguments without splitting (PR #94083)

[Jon Chesterfield via cfe-commits]

JonChesterfield wrote:

Slightly jumped the gun on this patch because Eli just wrote a bunch of useful things on #93362 and there's therefore a credible chance that rebasing on this will get the pass in the hands of other people soon, giving libc sprintf and so forth.

https://github.com/llvm/llvm-project/pull/94083