[Bug target/113960] std::map with std::vector as input overwrites itself with c++20, on s390x platform

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113960

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Oh I already defined a __is_memcmp_ordered_with trait, which does the same-size
check. I think that's what should be used here.