[clang] [llvm] [coro] Lower `llvm.coro.await.suspend.handle` to resume with tail call (PR #89751)

[Mircea Trofin via cfe-commits]

mtrofin wrote:

> I think my patch is a significant improvement, both in terms of simplicity and reliability of the codegen for symmetric transfer, and would like to move forward. @ChuanqiXu9 @mtrofin do you have any further comments?

Nothing on my side, lgtm for my narrow concern. Please wait for @ChuanqiXu9 's lgtm tho. 

https://github.com/llvm/llvm-project/pull/89751