[clang] [C++20][Coroutines] Lambda-coroutine with operator new in promise_type (PR #84193)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

This commit breaks our coroutines library async_simple `https://github.com/alibaba/async_simple` and here is a (relative) minimal reproducer: https://godbolt.org/z/sG5jzcGEz

The reproducer comes from an implementation for async_simple::Generator (https://github.com/alibaba/async_simple/blob/main/async_simple/coro/Generator.h), which is basically the same implementation from the paper of `std::generator` in c++23. So possibly this may make that crash too. 

I'll revert this patch to avoid the regression now. Sorry for not testing it sufficiently.

https://github.com/llvm/llvm-project/pull/84193