Tweak unittest compact config a bit and don't use it on bots.

pkg/barback/test/utils.dart

 // Copyright (c) 2013, 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 barback.test.utils;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/asset_graph.dart';
 import 'package:pathos/path.dart' as pathos;
 import 'package:scheduled_test/scheduled_test.dart';
-
-// TODO(rnystrom): Get rid of this or find a better path for it.
-import '../../../sdk/lib/_internal/pub/test/command_line_config.dart';
+import 'package:unittest/compact_vm_config.dart';
 
 var _configured = false;
 
 MockProvider _provider;
 AssetGraph _graph;
 
 /// Calls to [buildShouldSucceed] and [buildShouldFail] set expectations on
 /// successive [BuildResult]s from [_graph]. This keeps track of how many calls
 /// have already been made so later calls know which result to look for.
 int _nextBuildResult;
 
 void initConfig() {
   if (_configured) return;
   _configured = true;
-  unittestConfiguration = new CommandLineConfiguration();
+  useCompactVMConfiguration();
 }
 
 /// Creates a new [AssetProvider] and [AssetGraph] with the given [assets] and
 /// [transformers].
 ///
 /// This graph is used internally by most of the other functions in this
 /// library so you must call it in the test before calling any of the other
 /// functions.
 ///
 /// [assets] may either be an [Iterable] or a [Map]. If it's an [Iterable],
@@ skipping 432 matching lines @@
 
   MockAsset(this.id, this.contents);
 
   Future<String> readAsString({Encoding encoding}) =>
       new Future.value(contents);
 
   Stream<List<int>> read() => throw new UnimplementedError();
 
   String toString() => "MockAsset $id $contents";
 }