Run dartfmt on all files under runtime.

runtime/observatory/tests/service/vm_timeline_events_test.dart

 // Copyright (c) 2016, 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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'dart:async';
 import 'dart:developer';
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'service_test_common.dart';
@@ skipping 48 matching lines @@
       "recordedStreams": ["Dart"]
     });
   },
   (Isolate isolate) async {
     // Wait to receive events.
     await completer.future;
     cancelStreamSubscription(VM.kTimelineStream);
   },
 ];
 
-main(args) async => runIsolateTests(args,
-                                    tests,
-                                    testeeConcurrent: primeDartTimeline);
+main(args) async =>
+    runIsolateTests(args, tests, testeeConcurrent: primeDartTimeline);