Remove duplicate tests

Remove duplicate tests

These tests originally existed to check the containers in C++11 mode,
when the default was C++98 mode. Now that the default is C++14 (and we
run most tests for all modes) it serves no purpose to have two copies of
the tests when neither is explicitly using -std=gnu++98 anyway.

	* testsuite/23_containers/list/requirements/explicit_instantiation/
	5_c++0x.cc: Remove redundant test that is functionally identical to
	the 5.cc test.
	* testsuite/23_containers/map/requirements/explicit_instantiation/
	5_c++0x.cc: Likewise.
	* testsuite/23_containers/multimap/requirements/explicit_instantiation/
	5_c++0x.cc: Likewise.
	* testsuite/23_containers/multiset/requirements/explicit_instantiation/
	5_c++0x.cc: Likewise.
	* testsuite/23_containers/set/requirements/explicit_instantiation/
	5_c++0x.cc: Likewise.

From-SVN: r265329