Make List.from and Iterable.toList default to not growable.

runtime/lib/growable_array.dart

 // Copyright (c) 2012, 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.
 
 class _GrowableObjectArray<T> implements List<T> {
   factory _GrowableObjectArray._uninstantiable() {
     throw new UnsupportedError(
         "GrowableObjectArray can only be allocated by the VM");
   }
 
@@ skipping 298 matching lines @@
   }
 
   String toString() {
     return Collections.collectionToString(this);
   }
 
   Iterator<T> get iterator {
     return new ListIterator<T>(this);
   }
 
-  List<T> toList({ bool growable: false }) {
+  List<T> toList({ bool growable: true }) {
     return new List<T>.from(this, growable: growable);
   }
 
   Set<T> toSet() {
     return new Set<T>.from(this);
   }
 }