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

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 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 : )

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