Turn compile time errors related to missing getters and setters into invocation

tests/language/assign_top_method_negative_test.dart

Index: tests/language/assign_top_method_negative_test.dart
===================================================================
--- tests/language/assign_top_method_negative_test.dart	(revision 16462)
+++ tests/language/assign_top_method_negative_test.dart	(working copy)
@@ -1,10 +0,0 @@
-// 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.
-
-method() { return 0; }
-
-main() {
-  // Illegal, can't change a top level method
-  method = () { return 1; };
-}