Fix bound checking in self referencing type (issue 12553).

tests/language/f_bounded_quantification4_test.dart

Index: tests/language/f_bounded_quantification4_test.dart
===================================================================
--- tests/language/f_bounded_quantification4_test.dart	(revision 0)
+++ tests/language/f_bounded_quantification4_test.dart	(revision 0)
@@ -0,0 +1,16 @@
+// 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.
+
+// Test for F-Bounded Quantification.
+
+import "package:expect/expect.dart";
+
+class A<T extends B<T>> { }
+
+class B<T> extends A<T> { }
+
+main() {
+  Expect.equals("B<B>", new B<B>().runtimeType.toString());
+}
+