Add flag to disable capturing stack traces.

utils/tests/pub/oauth2/with_an_expired_credentials_refreshes_and_saves_test.dart

 // Copyright (c) 2012, 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:io';
 import 'dart:json' as json;
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:scheduled_test/scheduled_server.dart';
 
 import '../../../pub/io.dart';
 import '../../../pub/utils.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
+  initConfig();
   integration('with an expired credentials.json, refreshes and saves the '
       'refreshed access token to credentials.json', () {
     d.validPackage.create();
 
     var server = new ScheduledServer();
     d.credentialsFile(server, 'access token',
         refreshToken: 'refresh token',
         expiration: new DateTime.now().subtract(new Duration(hours: 1)))
         .create();
 
@@ skipping 22 matching lines @@
 
       request.response.close();
     });
 
     pub.shouldExit();
 
     d.credentialsFile(server, 'new access token', refreshToken: 'refresh token')
         .validate();
   });
 }