Add the ability to change the working directory

utils/testrunner/pipeline_utils.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.
 
 part of pipeline;
 
 List log;
 var replyPort;
 int _procId = 1;
 Map _procs = {};
@@ skipping 11 matching lines @@
 
 /**
  * Given a file path [file], make it absolute if it is relative,
  * and return the result as a [Path].
  */
 Path getAbsolutePath(String file) {
   var p = new Path(file).canonicalize();
   if (p.isAbsolute) {
     return p;
   } else {
-    var cwd = new Path((new Directory.current()).path);
+    var cwd = new Path(Directory.current.path);
     return cwd.join(p);
   }
 }
 
 /** Get the directory that contains a [file]. */
 String getDirectory(String file) =>
     getAbsolutePath(file).directoryPath.toString();
 
 /** Create a file [fileName] and populate it with [contents]. */
 void writeFile(String fileName, String contents) {
@@ skipping 160 matching lines @@
 
 void completePipeline(List stdout, List stderr, [exitCode = 0]) {
   replyPort.send([stdout, stderr, log, exitCode]);
 }
 
 /** Utility function to log diagnostic messages. */
 void logMessage(msg) => log.add(msg);
 
 /** Turn file paths into standard form with forward slashes. */
 String normalizePath(String p) => (new Path(p)).toString();