[clang] [clang] Fix lost lambda capture in dependent co_return operand (PR #220234)

[Avi Kivity via cfe-commits]

avikivity wrote:

> @avikivity I'd also consider adding this to the test
> 
> ```c++
> call([&](auto &t) -> coro_void {
>     co_await suspend_never{};
>     co_return use_void(p, t);
> });
> ```

Can you explain why? Does it exercise another path?

https://github.com/llvm/llvm-project/pull/220234