Implement LWG 2485

Implement LWG 2485

* include/debug/array (get(const array<_Tp, _Nm>&&)): New.
* include/std/array (get(const array<_Tp, _Nm>&&)): Likewise.
* include/std/tuple (get(const tuple<_Elements...>&&)): Likewise.
(get(const tuple<_Types...>&&)): Likewise.
* include/std/utility
(__pair_get::__const_move_get(const std::pair<_Tp1, _Tp2>&&)):
Likewise.
(get(const std::pair<_Tp1, _Tp2>&&)): Likewise.
(get(const pair<_Tp, _Up>&&)): Likewise.
(get(const pair<_Up, _Tp>&&)): Likewise.
* testsuite/20_util/pair/astuple/get.cc: Add tests for
new overloads.
* testsuite/20_util/pair/astuple/get_by_type.cc: Likewise.
* testsuite/20_util/tuple/element_access/get2.cc: Likewise.
* testsuite/20_util/tuple/element_access/get2_by_type.cc: Likewise.
* testsuite/23_containers/array/tuple_interface/get.cc: Likewise.
* testsuite/23_containers/array/tuple_interface/tuple_element_debug_neg.cc:
Adjust.
* testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc:
Likewise.

From-SVN: r254222