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/helpers/memory.hpp

@@ -181,9 +181,9 @@ namespace test
         }
     }
     
-    template <bool Value>
+    template <int Value>
     struct bool_type {
-        enum { value = Value };
+        enum { value = (Value ? true : false) };
     };
 
     struct true_type {
@@ -194,15 +194,6 @@ namespace test
         enum { value = false };
     };
 
-    template <typename Alloc>
-    struct is_select_on_copy : false_type {};
-    template <typename Alloc>
-    struct is_propagate_on_swap : false_type {};
-    template <typename Alloc>
-    struct is_propagate_on_assign : false_type {};
-    template <typename Alloc>
-    struct is_propagate_on_move : false_type {};
-
     template <typename Alloc>
     int selected_count(Alloc const&)
     {