Migrate the language tests up to arithmetic_test.

tests/language_strong/abstract_object_method_test.dart

Index: tests/language_strong/abstract_object_method_test.dart
diff --git a/tests/language_strong/abstract_object_method_test.dart b/tests/language_strong/abstract_object_method_test.dart
deleted file mode 100644
index 2d4af77c7ea5a1654c20b60f2236d27599fbc956..0000000000000000000000000000000000000000
--- a/tests/language_strong/abstract_object_method_test.dart
+++ /dev/null
@@ -1,25 +0,0 @@
-// 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.
-
-import "package:expect/expect.dart";
-
-class A {
-  noSuchMethod(_) {
-    Expect.fail('Should not reach here');
-  }
-}
-
-class B extends A {
-  operator ==(other);
-}
-
-class C extends B {}
-
-var a = [new C()];
-
-main() {
-  C c = a[0];
-  a.add(c);
-  Expect.isTrue(c == a[1]);
-}