We optimize _Destroy and _Destroy_n to do nothing when the type has a
trivial destructor, which means we do nothing (instead of giving an
error) when trying to destroy types with deleted destructors.

Because deleted destructors are trivial. Because C++.

This adds static assertions to reject attempts to destroy
indestructible objects. I put them in the top-level functions, not the
specialization for trivial destructors, which means we also get the
static assertion for types with a private destructor. It's debatable
whether that's better: you get a failed "type is destructible"
assertion instead of an error saying the destructor is private, which
is a bit more precise. If people prefer the compiler error about a
private destructor we could move the assertions into the
specializations for types with trivial destructors.

	PR libstdc++/80553
	* include/bits/stl_construct.h (_Destroy, _Destroy_n): Add static
	assertions to ensure type is destructible.
	(destroy_at, destroy, destroy_n): Move from stl_uninitialized.h.
	* include/bits/stl_uninitialized.h (destroy_at, destroy, destroy_n):
	Move to stl_construct.h.
	* testsuite/20_util/specialized_algorithms/memory_management_tools/
	destroy_neg.cc: New test.
	* testsuite/23_containers/vector/cons/destructible_neg.cc: New test.

Tested powerpc64le-linux, committed to trunk.