Format all tests.

tests/language/generic_constructor_mixin2_test.dart

 // Copyright (c) 2014, 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.
 
 // Test that parameter types types are checked correctly in the face of
 // mixin application upon a generic constructor.
 
 import 'checked_mode_helper.dart';
 
 class A<X> {
   A(X x);
 }
 
 class B {}
+
 class C {}
 
 class D<Y> = A<Y> with B, C;
 
 void main() {
   var v = 0;
   checkNoDynamicTypeError(() => new D<int>(v));
   checkDynamicTypeError(() => new D<String>(v));
 }