dart2js: run dartfmt on tests

tests/compiler/dart2js/js_constant_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.
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'compiler_helper.dart';
 
 const String TEST_1 = r"""
   import 'dart:_foreign_helper';
   main() {
     JS('', '#.toString()', -5);
     // absent: "5.toString"
     // present: "(-5).toString"
   }
 """;
 
-
 main() {
   RegExp directivePattern = new RegExp(
       //      \1                    \2        \3
       r'''// *(present|absent): (?:"([^"]*)"|'([^'']*)')''',
       multiLine: true);
 
   Future check(String test) {
     Uri uri = new Uri(scheme: 'dart', path: 'test');
     var compiler = compilerFor(test, uri, expectedErrors: 0);
     return compiler.run(uri).then((_) {
@@ skipping 10 matching lines @@
         } else {
           assert(directive == 'absent');
           Expect.isFalse(generated.contains(pattern),
               "Must not find '$pattern' in:\n$generated");
         }
       }
     });
   }
 
   asyncTest(() => Future.wait([
-    check(TEST_1),
-  ]));
+        check(TEST_1),
+      ]));
 }