PR middle-end/92761 - hash_table::expand invokes assignment on invalid objects

PR middle-end/92761 - hash_table::expand invokes assignment on invalid objects

PR middle-end/92761 - hash_table::expand invokes assignment on invalid objects
PR middle-end/92762 - hash_table::empty_slow invokes assignment on invalid objects

gcc/ChangeLog:

	PR middle-end/92761
	PR middle-end/92762
	* hash-map-tests.c (test_map_of_type_with_ctor_and_dtor): Tighten
	up tests.
	* hash-table.h (hash_table::expand): Use placement new to copy
	construct objects in uninitialized storage.
	(hash_table::empty_slow): Avoid invoking copy assignment on
	uninitialized objects.

From-SVN: r279139