[Bug c++/110855] std::source_location doesn't work with C++20 coroutine

[arsen at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110855

--- Comment #5 from Arsen Arsenović <arsen at gcc dot gnu.org> ---
agreed, but note that it still gives us the name of the actor function:

  pr110855.C:51:1ReturnObject bar(int)
  pr110855.C:51:1void bar(bar(int)::_Z3bari.Frame*)

(the latter print is from initial_suspend)

this is probably not ideal, but I'm unsure what that'd be expected to be anyway
(given that it's in a bunch of synthesized code)