Create associated packages for the dart:collection and dart:async libs.

pkg/collection/test/algorithms_test.dart

 // Copyright (c) 2013, 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.
 
 /// Tests algorithm utilities.
 
-import "package:collection_helpers/all.dart";
+import "package:collection/collection.dart";
 import "package:unittest/unittest.dart";
 import 'dart:math';
 
 void main() {
   void testShuffle(List list) {
     List copy = list.toList();
     shuffle(list);
     expect(new UnorderedIterableEquality().equals(list, copy), isTrue);
   }
 
@@ skipping 243 matching lines @@
   C(this.id);
 }
 int compareC(C one, C other) => one.id - other.id;
 
 class OC implements Comparable<OC> {
   final int id;
   final int order;
   OC(this.id, this.order);
   int compareTo(OC other) => id - other.id;
   String toString() => "OC[$id,$order]";
-}
+}