[llvm] [clang] [coroutine] Implement llvm.coro.await.suspend intrinsic (PR #79712)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

BTW, in my original comment, I said:

> Then in the middle end, we can perform analysis the awaitSuspendFn to see if the coroutine handle escapes or not. If it won't escape, we can replace above intrinsic to the direct call. Otherwise, we will only convert them in the CoroSplit phase.

But this patch only implements the otherwise part. This is not a blocking issue. But we need a TODO or a FIXME here.

https://github.com/llvm/llvm-project/pull/79712