pkg/smoke: support latest analyzer version and formatted code

test/mirrors_used_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.
 
 library smoke.test.mirrors_test;
 
 import 'package:smoke/mirrors.dart';
 import 'package:unittest/unittest.dart';
 import 'common.dart' hide main;
 import 'common.dart' as common show main;
 
-
 @MirrorsUsed(
     targets: const [A, B, C, D, E, E2, F, F2, G, H, Type],
     override: 'smoke.mirrors')
 import 'dart:mirrors';
 
 main() {
   setUp(useMirrors);
   common.main();
 }