While both compilers have warnings when noreturn functions return or fall through to the end of function, the actual UB happens only if that actually happens at runtime,
so I think it makes sense to sanitize that (though, it is even worse UB than -fsanitize=return and it doesn't make any sense to try to recover from that, after all the compilers
won't do anything meaningful in the caller usually, it can end up in a different function or unrelated code etc.
No tests included, as this is just the library side, somebody from the LLVM camp would need to add (very simple) compiler changes.