Revert "Wrote functions to convert collections and maps to strings and invoked"

corelib/src/implementation/hash_map_set.dart

Index: corelib/src/implementation/hash_map_set.dart
diff --git a/corelib/src/implementation/hash_map_set.dart b/corelib/src/implementation/hash_map_set.dart
index c538951fff31beb62674103b8c7517339c0c8ded..6290b8f2aa80b05fe07bdb9bddf59a80efbb1fc7 100644
--- a/corelib/src/implementation/hash_map_set.dart
+++ b/corelib/src/implementation/hash_map_set.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2011, 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.
 
@@ -268,10 +268,6 @@ class HashMapImplementation<K extends Hashable, V> implements HashMap<K, V> {
     }
     return false;
   }
-
-  String toString() {
-    return Maps.mapToString(this);
-  }
 }
 
 class HashSetImplementation<E extends Hashable> implements HashSet<E> {
@@ -380,10 +376,6 @@ class HashSetImplementation<E extends Hashable> implements HashSet<E> {
     return new HashSetIterator<E>(this);
   }
 
-  String toString() {
-    return Collections.collectionToString(this);
-  }
-
   // The map backing this set. The associations in this map are all
   // of the form element -> element. If a value is not in the map,
   // then it is not in the set.