[Bug c++/97438] [accepts-invalid] coroutines accepts prmomise type with both return_value() and return_void()

[avi--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97438

--- Comment #5 from Avi Kivity <a...@cloudius-systems.com> ---
No pressing reason to backport (for me gcc coroutines are useless anyway due to
95137)