Format all tests.

tests/language_strong/label5_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.
 // Dart test program to test check that we catch label errors.
 
-
 class Label5NegativeTest {
   static testMain() {
     var L = 33;
     while (false) {
       if (true) break L; // Illegal: L is not a label.
     }
   }
 }
 
-
 main() {
   Label5NegativeTest.testMain();
 }