Add deduction guides for sequence containers (P0433R2, partial)

Add deduction guides for sequence containers (P0433R2, partial)

	* include/bits/forward_list.h (forward_list): Add deduction guide.
	* include/bits/stl_deque.h (deque): Likewise.
	* include/bits/stl_list.h (list): Likewise.
	* include/bits/stl_vector.h (vector): Likewise.
	* testsuite/23_containers/deque/cons/deduction.cc: New.
	* testsuite/23_containers/forward_list/cons/deduction.cc: New.
	* testsuite/23_containers/list/cons/deduction.cc: New.
	* testsuite/23_containers/vector/cons/deduction.cc: New.

From-SVN: r249054