[llvm] [Coroutines] [NFCI] Don't search the DILocalVariable for __promise when constructing the debug varaible for __coro_frame (PR #105626)

[Chuanqi Xu via llvm-commits]

ChuanqiXu9 wrote:

I realized why this received regression reports (https://github.com/llvm/llvm-project/commit/08a0dece2b2431db8abe650bb43cba01e781e1ce#commitcomment-145619095) is that, in `debug lines only` mode, we won't generate debug information for the promise alloca. Then the previous version just works surprisingly.

However, after we optimize this, we tried to always to generate the debug info. But I didn't realize that it is possible we're going to generate debug info but not the debug info for local variables (the -glm case).

@alinas @gribozavr Could you try to test this in your code bases to avoid breaking your repo again?

https://github.com/llvm/llvm-project/pull/105626