Update or delete language tests using obsolete interfaces or default factory

tests/language/instanceof_test.dart

Index: tests/language/instanceof_test.dart
===================================================================
--- tests/language/instanceof_test.dart	(revision 15648)
+++ tests/language/instanceof_test.dart	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 
@@ -168,13 +168,13 @@
   }
 }
 
-interface I {}
+abstract class I {}
 class A implements I {A() {}}
 class B {B() {}}
 
-interface J {}
+abstract class J {}
 
-interface K extends J {}
+abstract class K implements J {}
 class C implements I, K {C() {}}
 
 class D extends C {D() : super() {}}