Regressions on trunk at revision 174810 vs revision 174806

[H.J. Lu ia32]

New failures:

New passes:
FAIL: 20_util/is_copy_assignable/value.cc (test for excess errors)
FAIL: 20_util/is_move_assignable/value.cc (test for excess errors)
FAIL: 20_util/is_nothrow_copy_assignable/value.cc (test for excess errors)
FAIL: 20_util/unique_ptr/cons/pointer_array_convertible_neg.cc (test for excess errors)
FAIL: 23_containers/unordered_multimap/insert/multimap_single.cc (test for excess errors)
FAIL: 23_containers/unordered_set/insert/set_range.cc (test for excess errors)