Move Arrays, Collections and Maps into a new library, dart:collections.

lib/collections/collections.dart

Index: lib/collections/collections.dart
diff --git a/tests/language/first_class_types_lib1.dart b/lib/collections/collections.dart
similarity index 83%
copy from tests/language/first_class_types_lib1.dart
copy to lib/collections/collections.dart
index baadc66015a5ced9bfbdc10f1180715ee714a547..d1673778f420ce91a259cc282ff3f30a19828099 100644
--- a/tests/language/first_class_types_lib1.dart
+++ b/lib/collections/collections.dart
@@ -2,6 +2,6 @@
 // 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.
 
-library lib1;
+library collections;
 
-class A {}
+part 'helpers.dart';