[clang] [Clang][AMDGPU] Stop defaulting to `one-as` for all atomic scopes (PR #120095)

[Pierre van Houtryve via cfe-commits]

Pierre-vh wrote:

I'm trying to understand this. Is the function being changed a generic util called by multiple builtins, and this change is just to make `one-as` exclusive to the OpenCL variant of those builtins ?
Can an identical builtin have different behavior depending on the input language (e.g. OpenCL or C++ mode) ?

https://github.com/llvm/llvm-project/pull/120095