Unordered: Fix some portability issues in tests.

- Simplify mechanism for detecting traits of test allocators. There were
  some portability issues, but rather than fix them I've just gone for a
  simpler mechanism. Does mean that the relevant tests can't be run for
  other allocators.
- Fix a couple of unnecessary_copy_tests, whose results were the wrong
  way round.
- It appears that Visual C++ only implements RVO for implicitly defined
  copy constructors in debug mode, so adjust a move_test to account for
  the extra copies now that the copy constructors are explicitly
  defined.

[SVN r73798]

test/unordered/assign_tests.cpp

@@ -99,7 +99,7 @@ void assign_tests2(T*,
         x2 = x1;
         BOOST_TEST(test::equivalent(x2.hash_function(), hf1));
         BOOST_TEST(test::equivalent(x2.key_eq(), eq1));
-        if (test::is_propagate_on_assign<allocator_type>::value) {
+        if (allocator_type::is_propagate_on_assign) {
             BOOST_TEST(test::equivalent(x2.get_allocator(), al1));
             BOOST_TEST(!test::equivalent(x2.get_allocator(), al2));
         }
@@ -161,6 +161,19 @@ boost::unordered_multimap<test::object, test::object,
 using test::default_generator;
 using test::generate_collisions;
 
+template <typename T>
+bool is_propagate(T*)
+{
+    return T::allocator_type::is_propagate_on_assign;
+}
+
+UNORDERED_AUTO_TEST(check_traits)
+{
+    BOOST_TEST(!is_propagate(test_set));
+    BOOST_TEST(is_propagate(test_set_prop_assign));
+    BOOST_TEST(!is_propagate(test_set_no_prop_assign));
+}
+
 UNORDERED_TEST(assign_tests1, (
         (test_set)(test_multiset)(test_map)(test_multimap)
         (test_set_prop_assign)(test_multiset_prop_assign)(test_map_prop_assign)(test_multimap_prop_assign)