Run dartfmt on all files under runtime.

runtime/observatory/tests/service/async_next_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.
 // VMOptions=--error_on_bad_type --error_on_bad_override  --verbose_debug
 
 import 'package:observatory/service_io.dart';
 import 'service_test_common.dart';
 import 'test_helper.dart';
 import 'dart:developer';
 
 const int LINE_A = 19;
 const int LINE_B = 20;
 const int LINE_C = 21;
 
-foo() async { }
+foo() async {}
 
 doAsync(stop) async {
   if (stop) debugger();
   await foo(); // Line A.
   await foo(); // Line B.
   await foo(); // Line C.
   return null;
 }
 
 testMain() {
@@ skipping 16 matching lines @@
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_B),
   stepOver, // foo()
   asyncNext,
   hasStoppedAtBreakpoint,
   stoppedAtLine(LINE_C),
   resumeIsolate,
 ];
 
 main(args) => runIsolateTests(args, tests, testeeConcurrent: testMain);