libstdc++: Make debug containers prefer copy ctor to base ctor (PR 90102)

libstdc++: Make debug containers prefer copy ctor to base ctor (PR 90102)

When given a type which can convert to any container-like type, the
C(const C&) copy constructor and C(const C::_Base&) converting
constructor are ambiguous. This change replaces the converting
constructor's parameter with a reference_wrapper-like type so that
calling that constructor requires an additional user-defined conversion.
This gives it a lower rank than the copy constructor, avoiding the
ambiguity.

While testing this change I discovered that __gnu_debug::forward_list
doesn't have a convering constructor from the std::forward_list base, so
this adds it.

We should probably consider whether the converting constructors should
be 'explicit' but I'm not changing that now.

libstdc++-v3/ChangeLog:

	PR libstdc++/90102
	* include/debug/deque (deque(const _Base&)): Replace parameter
	with a struct that wraps a const _Base&.
	* include/debug/forward_list (forward_list(_Base_ref)): New
	constructor.
	* include/debug/list (list(const _Base&)): Replace parameter
	with a struct that wraps a const _Base&.
	* include/debug/map.h (map(const _Base&)): Likewise.
	* include/debug/multimap.h (multimap(const _Base&)): Likewise.
	* include/debug/multiset.h (multiset(const _Base&)): Likewise.
	* include/debug/set.h (set(const _Base&)): Likewise.
	* include/debug/unordered_map (unordered_map(const _Base&))
	(unordered_multimap(const _Base&)): Likewise.
	* include/debug/unordered_set (unordered_set(const _Base&))
	(unordered_multiset(const _Base&)): Likewise.
	* testsuite/23_containers/vector/cons/destructible_debug_neg.cc:
	Adjust dg-error line number.
	* include/debug/vector (vector(const _Base&)): Likewise.
	* testsuite/23_containers/deque/debug/90102.cc: New test.
	* testsuite/23_containers/forward_list/debug/90102.cc: New test.
	* testsuite/23_containers/list/debug/90102.cc: New test.
	* testsuite/23_containers/map/debug/90102.cc: New test.
	* testsuite/23_containers/multimap/debug/90102.cc: New test.
	* testsuite/23_containers/multiset/debug/90102.cc: New test.
	* testsuite/23_containers/set/debug/90102.cc: New test.
	* testsuite/23_containers/unordered_map/debug/90102.cc: New test.
	* testsuite/23_containers/unordered_multimap/debug/90102.cc: New test.
	* testsuite/23_containers/unordered_multiset/debug/90102.cc: New test.
	* testsuite/23_containers/unordered_set/debug/90102.cc: New test.
	* testsuite/23_containers/vector/debug/90102.cc: New test.