Add flag to disable capturing stack traces.

utils/tests/pub/install/hosted/unlock_if_new_is_unsatisfied_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.
 
 library pub_tests;
 
 import 'dart:io';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
+  initConfig();
   integration("unlocks dependencies if necessary to ensure that a new "
       "dependency is satisfied", () {
     servePackages([
       packageMap("foo", "1.0.0", [dependencyMap("bar", "<2.0.0")]),
       packageMap("bar", "1.0.0", [dependencyMap("baz", "<2.0.0")]),
       packageMap("baz", "1.0.0", [dependencyMap("qux", "<2.0.0")]),
       packageMap("qux", "1.0.0")
     ]);
 
     d.appDir([dependencyMap("foo")]).create();
@@ skipping 23 matching lines @@
 
     d.packagesDir({
       "foo": "2.0.0",
       "bar": "2.0.0",
       "baz": "2.0.0",
       "qux": "1.0.0",
       "newdep": "2.0.0"
     }).validate();
   });
 }