Move some core classes to collection library.

Review URL: https://codereview.chromium.org//11867024

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@17352 260f80e4-7a28-3924-810f-c04153c831b5
diff --git a/test/utils.dart b/test/utils.dart
index cf5bff2..2b6c1a7 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -5,6 +5,7 @@
 library utils;
 
 import 'dart:async';
+import 'dart:collection' show Queue;
 
 import '../../unittest/lib/unittest.dart';
 import '../../http/lib/http.dart' as http;