The extension that allows implicitly rebinding a container's allocator
is not allowed when _GLIBCXX_CONCEPT_CHECKS is defined, so skip the
tests for that extension.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* testsuite/23_containers/deque/requirements/explicit_instantiation/3.cc:
	Do not test implicit allocator rebinding when _GLIBCXX_CONCEPT_CHECKS
	is defined.
	* testsuite/23_containers/forward_list/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/list/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/list/requirements/explicit_instantiation/5.cc:
	Likewise.
	* testsuite/23_containers/map/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/map/requirements/explicit_instantiation/5.cc:
	Likewise.
	* testsuite/23_containers/multimap/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/multimap/requirements/explicit_instantiation/5.cc:
	Likewise.
	* testsuite/23_containers/multiset/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/multiset/requirements/explicit_instantiation/5.cc:
	Likewise.
	* testsuite/23_containers/set/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/set/requirements/explicit_instantiation/5.cc:
	Likewise.
	* testsuite/23_containers/unordered_map/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/unordered_multimap/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/unordered_multiset/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/unordered_set/requirements/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/vector/ext_pointer/explicit_instantiation/3.cc:
	Likewise.
	* testsuite/23_containers/vector/requirements/explicit_instantiation/3.cc:
	Likewise.

Tested x86_64-linux. Committed to trunk.