[llvm] [AMDGPU] Extend wave reduce intrinsics for i32 type (PR #126469)

[via llvm-commits]

easyonaadit wrote:

> > We need clang builtins and unit tests to ensure these really work
> 
> I could put some unit tests in `libc` if needed. I currently test the `scan` helpers in `gpuintrin.h` there.

Are we looking for tests to check the codegen only or do we need execution tests?

https://github.com/llvm/llvm-project/pull/126469