[Bug libstdc++/125220] std::priority_queue move constructs twice and move assigns upon emplace

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125220

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
But for additional insertions into the queue, we still do too many operations.

Our push_heap seems wasteful.