Allow self referencing typedefs (issue 2490).

tests/language/function_type_alias_negative_test.dart

Index: tests/language/function_type_alias_negative_test.dart
===================================================================
--- tests/language/function_type_alias_negative_test.dart	(revision 7399)
+++ tests/language/function_type_alias_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.
-// Dart test for illegally self referencing function type alias.
-
-typedef Handle Handle(String command);
-
-main() {
-  Handle handle = null;
-}