[llvm] [Coroutines][NFC] Refactor CoroCloner (PR #116885)

[Tyler Nowicki via llvm-commits]

TylerNowicki wrote:

> > Ping. Any issues with this one? I will do this for other ABIs and eventually move the header to include/llvm/Transforms/Coroutines.
> 
> Reviewers may not be available all the time in LLVM : )

Yes, I realized that many people have probably taken the week off for American Thanksgiving. I will be patient...

https://github.com/llvm/llvm-project/pull/116885