Constrain constant references from deferred libraries

tests/compiler/dart2js_extra/deferred/deferred_constant5_test.dart

-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import 'package:async_helper/async_helper.dart';
-import 'package:expect/expect.dart';
-
-import 'dart:async';
-
-@lazy import 'deferred_class_library2.dart' as lib;
-
-const lazy = const DeferredLibrary('deferred_class_library2');
-
-main() {
-  asyncStart();
-  lazy.load().then((bool didLoad) {
-    Expect.isTrue(didLoad);
-    Expect.equals(321, const lib.Gee.n321().value);
-    Expect.equals(246, const lib.Gee.n246().value);
-    Expect.equals(888, const lib.Gee.n888().value);
-    Expect.equals(321, const lib.Gee2.n321().value);
-    Expect.equals(151, const lib.Gee2.n151().value);
-    Expect.equals(888, const lib.Gee2.n888().value);
-    asyncEnd();
-  });
-}