Implement N4258 (Cleaning-up noexcept in the Library rev 3)

Implement N4258 (Cleaning-up noexcept in the Library rev 3)

	* doc/xml/manual/intro.xml: Document LWG 2108 status.
	* include/bits/alloc_traits.h (allocator_traits::is_always_equal):
	Define.
	* include/bits/allocator.h (allocator::is_always_equal): Likewise.
	* include/bits/forward_list.h
	(forward_list::operator=(forward_list&&)): Use __bool_constant.
	(forward_list::swap(forward_list&)): Add noexcept.
	* include/bits/hashtable.h (_Hashtable::operator=(_Hashtable&&)):
	Likewise.
	(_Hashtable::swap(_Hashtable&)): Likewise.
	* include/bits/stl_deque.h (_Deque_base::_Deque_base(_Deque_base&&)):
	Use _Alloc_traits::is_always_equal.
	(deque::operator=(deque&&)): Likewise.
	(deque::_M_move_assign1(deque&&, false_type)): Add comment and use
	__bool_constant.
	(swap(deque&, deque&)): Add noexcept.
	* include/bits/stl_list.h (list::operator=(list&&)): Use
	__bool_constant.
	(swap(list&, list&)): Add noexcept.
	* include/bits/stl_map.h (map::swap(map&)): Include _Compare in
	noexcept.
	(swap(map&, map&)): Add noexcept.
	* include/bits/stl_multimap.h (multimap::swap(multimap&)): Include
	_Compare in noexcept.
	(swap(multimap&, multimap&)): Add noexcept.
	* include/bits/stl_multiset.h (multiset::swap(multiset&)): Include
	_Compare in noexcept.
	(swap(multiset&, multiset&)): Add noexcept.
	* include/bits/stl_set.h (set::swap(set&)): Include _Compare in
	noexcept.
	(swap(set&, set&)): Add noexcept.
	* include/bits/stl_tree.h (_Rb_tree::operator=(_Rb_tree&&)): Include
	_Compare in noexcept.
	(_Rb_tree::_Rb_tree(_Rb_tree&&, _Node_alloc_type&&)): Use
	is_always_equal.
	* include/bits/stl_vector.h (vector::operator=(vector&&)): Use
	__bool_constant.
	(swap(vector&, vector&)): Add noexcept.
	* include/bits/unordered_map.h (swap(unordered_map&, unordered_map&),
	swap(unordered_multimap& unordered_multimap&)): Add noexcept.
	* include/bits/unordered_set.h (swap(unordered_set&, unordered_set&),
	swap(unordered_multiset& unordered_multiset&)): Add noexcept.
	* include/ext/alloc_traits.h (__allocator_always_compares_equal):
	Remove.
	(__alloc_traits::_S_always_equal()): Use is_always_equal instead of
	__allocator_always_compares_equal.
	* include/ext/array_allocator.h (array_allocator::is_always_equal):
	Define.
	* include/std/scoped_allocator (__any_of, __propagate_on_copy,
	__propagate_on_move, __propagate_on_swap): Remove.
	(scoped_allocator_adaptor::propagate_on_container_copy_assignment,
	scoped_allocator_adaptor::propagate_on_container_move_assignment,
	scoped_allocator_adaptor::propagate_on_container_swap): Define with
	__and_ instead of __any_of.
	(scoped_allocator_adaptor::is_always_equal): Define.
	* testsuite/20_util/allocator_traits/members/is_always_equal.cc: New.
	* testsuite/20_util/scoped_allocator/propagation.cc: Make traits
	derive from true_type or false_type.
	* testsuite/23_containers/deque/allocator/move_assign-2.cc: Add
	is_always_equal member and remove the trait specialization.
	* testsuite/23_containers/vector/52591.cc: Likewise.
	* testsuite/23_containers/deque/requirements/dr438/assign_neg.cc:
	Adjust dg-error line number.
	* testsuite/23_containers/deque/requirements/dr438/
	constructor_1_neg.cc: Likewise.
	* testsuite/23_containers/deque/requirements/dr438/
	constructor_2_neg.cc: Likewise.
	* testsuite/23_containers/deque/requirements/dr438/insert_neg.cc:
	Likewise.
	* testsuite/23_containers/list/requirements/dr438/assign_neg.cc:
	Likewise.
	* testsuite/23_containers/list/requirements/dr438/constructor_1_neg.cc:
	Likewise.
	* testsuite/23_containers/list/requirements/dr438/insert_neg.cc:
	Likewise.
	* testsuite/23_containers/vector/requirements/dr438/assign_neg.cc:
	Likewise.
	* testsuite/23_containers/vector/requirements/dr438/
	constructor_1_neg.cc: Likewise.
	* testsuite/23_containers/vector/requirements/dr438/
	constructor_2_neg.cc: Likewise.
	* testsuite/23_containers/vector/requirements/dr438/insert_neg.cc:
	Likewise.

From-SVN: r225081