[Bug c/92479] missing warnings for unreachable codes with -Wunreachable-code

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92479

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The code for Wunreachable-code was removed a long time ago (around 5-10 years
ago).