Format all tests.

tests/language_strong/interface2_negative_test.dart

 // 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.
 // Dart test program for testing wrong abstract class reference:
 // A class must implement a known interface.
 
-
 class Interface2NegativeTest implements BooHoo {
-  static testMain() {
-  }
+  static testMain() {}
 }
 
 main() {
   Interface2NegativeTest.testMain();
 }