Format all tests.

tests/language/super_mixin_test.dart

 // Copyright (c) 2015, 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.
 
 // Dart2js regression test: Test that the type mask for non-null exact Mixin is
 // created for Mixin.getter.
 
 import 'package:expect/expect.dart';
 
 class Mixin {
   @NoInline()
   get getter => 42;
 }
 
-class Superclass {
-
-}
+class Superclass {}
 
 class Subclass extends Superclass with Mixin {
   method() => super.getter;
 }
 
 void main() {
   Expect.equals(42, new Subclass().method());
-}
+}