Move toString() to collection classes.

tests/corelib/list_to_string2_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.
 
 import "package:expect/expect.dart";
 
-class A {
-  a(x) => x + 1;
-}
+main() {
+  List list = [1, 2];
+  list.add(list);
+  
+  List list2 = new List(4);
+  list2[0] = 1;
+  list2[1] = 2;
+  list2[2] =list2;
+  list2[3] = list;
+  
+  Expect.equals("[1, 2, [...]]", list.toString());
+  Expect.equals("[1, 2, [...], [1, 2, [...]]]", list2.toString());
 
-f(p) => p("A");
-
-main() {
-  A a = new A();
-  a.a(1);
-  var v = null;
-  try {
-    v = f(a.a);
-  } catch (e) { }
-
-  Expect.equals(null, v);
-}
+}