Update dart:io tests to use asyncStart/asyncEnd

tests/standalone/io/directory_error_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.
 //
 // Dart test program for testing error handling in directory I/O.
 
-import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
-import "dart:isolate";
+
+import "package:async_helper/async_helper.dart";
+import "package:expect/expect.dart";
 
 Directory tempDir() {
   return new Directory('').createTempSync();
 }
 
 
 bool checkCreateInNonExistentFileException(e) {
   Expect.isTrue(e is DirectoryException);
   Expect.isTrue(e.osError != null);
   Expect.isTrue(e.toString().indexOf("Creation failed") != -1);
@@ skipping 171 matching lines @@
               done();
             });
 }
 
 
 void runTest(Function test) {
   // Create a temporary directory for the test.
   var temp = new Directory('').createTempSync();
 
   // Wait for the test to finish and delete the temporary directory.
-  ReceivePort p = new ReceivePort();
-  p.receive((x,y) {
-    p.close();
-    temp.deleteSync(recursive: true);
-  });
+  asyncStart();
 
   // Run the test.
-  test(temp, () => p.toSendPort().send(null));
+  test(temp, () {
+    temp.deleteSync(recursive: true);
+    asyncEnd();
+  });
 }
 
 
 main() {
   runTest(testCreateInNonExistent);
   runTest(testCreateTempInNonExistent);
   runTest(testDeleteNonExistent);
   runTest(testDeleteRecursivelyNonExistent);
   runTest(testListNonExistent);
   runTest(testRenameNonExistent);
   runTest(testRenameFileAsDirectory);
   runTest(testRenameOverwriteFile);
 }