[llvm] [Coroutines] Move materialization code into its own utils (PR #108240)

[Chuanqi Xu via llvm-commits]

https://github.com/ChuanqiXu9 approved this pull request.

LGTM. As before I didn't check it line by line but assumes you are doing trivial code movements.

https://github.com/llvm/llvm-project/pull/108240