Revert two Kernel changes that were causing test failures.

tests/language_strong/assign_instance_method_negative_test.dart

 // 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;
-    };
-  });
+  var a = new A();
+  // Illegal, can't change a member method
+  a.imethod = () {
+    return 1;
+  };
 }