[libc++] Implement the resolutions of LWG3506 and LWG3522.

Implement the changes in all language modes.

LWG3506 "Missing allocator-extended constructors for priority_queue"
makes the following changes:
- New allocator-extended constructors for priority_queue.
- New deduction guides targeting those constructors.

LWG3522: "Missing requirement on InputIterator template parameter
for priority_queue constructors". The iterator parameter should be
constrained to actually be an iterator type. `priority_queue{1,2}`
should be SFINAE-friendly ill-formed.

Also, do a drive-by fix in the allocator-extended move constructor:
there's no need to do a `make_heap` after moving from `__q.c` into
our own `c`, because that container was already heapified when it
was part of `__q`. [priqueue.cons.alloc] actually specifies the
behavior and does *not* mention calling `make_heap`. I think this
was just a copy-paste thinko. It dates back to the initial import
of libc++.

Differential Revision: https://reviews.llvm.org/D106824
Differential Revision: https://reviews.llvm.org/D106827

GitOrigin-RevId: 3894a8a4768fd6fa9bf18303a0db1687c7c687b3
9 files changed