[Bug libstdc++/86013] std::vector::shrink_to_fit() could sometimes use realloc()

[jan.kratochvil at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86013

--- Comment #2 from Jan Kratochvil <jan.kratochvil at redhat dot com> ---
You apparently know better all the pitfalls, I just got shocked that a
squeezing shrink_to_fit() does a copy.