Revert two Kernel changes that were causing test failures.

tests/language_2/assign_instance_method_test.dart

Index: tests/language_2/assign_instance_method_test.dart
diff --git a/tests/language_2/assign_instance_method_test.dart b/tests/language_2/assign_instance_method_test.dart
deleted file mode 100644
index 0b4fa3583615346441b47f3302399abd1219b198..0000000000000000000000000000000000000000
--- a/tests/language_2/assign_instance_method_test.dart
+++ /dev/null
@@ -1,23 +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.
-
-import 'package:expect/expect.dart';
-
-class A {
-  A() {}
-  imethod() {
-    return 0;
-  }
-}
-
-main() {
-  dynamic a = new A();
-
-  // Illegal, can't change a member method.
-  Expect.throws(() {
-    a.imethod = () {
-      return 1;
-    };
-  });
-}