[clang] [C++20][Coroutines] lambda-coroutine with promise_type ctor. (PR #84519)

[Andreas Fertig via cfe-commits]

andreasfertig wrote:

@ChuanqiXu9 here is a dedicated patch to support a `promise_type` with a user-provided constructor in a coroutine used with a lambda.

https://github.com/llvm/llvm-project/pull/84519