Format all tests.

tests/language/interface_static_non_final_fields_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.
 
 abstract class A {
   static var a;
 }
 
 class InterfaceStaticNonConstFieldsNegativeTest {
-
-  static testMain() {
-  }
+  static testMain() {}
 }
 
 main() {
   InterfaceStaticNonFinalFieldsNegativeTest.testMain();
 }