Update dart:io tests to use asyncStart/asyncEnd

tests/standalone/io/file_invalid_arguments_test.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.
 
 import "dart:async";
+import "dart:io";
+
+import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
-import "dart:io";
-import "dart:isolate";
 
 void testReadInvalidArgs(arg) {
   String filename = getFilename("tests/vm/data/fixed_length_file");
   var file = (new File(filename)).openSync();
   Expect.throws(() => file.readSync(arg),
                 (e) => e is ArgumentError);
 
   Expect.throws(() => file.read(arg),
                 (e) => e is ArgumentError);
 }
@@ skipping 52 matching lines @@
   Expect.throws(() => ((x, y) =>
       FileSystemEntity.typeSync(x, followLinks: y))(".", "why not?"));
   Expect.throws(() => ((x, y) =>
       FileSystemEntity.identicalSync(x, y))([1,2,3], "."));
   Expect.throws(() => ((x, y) =>
                        FileSystemEntity.identicalSync(x, y))(".", 52));
   Expect.throws(() => ((x) => FileSystemEntity.isLinkSync(x))(52));
   Expect.throws(() => ((x) => FileSystemEntity.isFileSync(x))(52));
   Expect.throws(() => ((x) => FileSystemEntity.isDirectorySync(x))(52));
 
-  ReceivePort keepAlive = new ReceivePort();
+  asyncStart();
   futureThrows(((x) => FileSystemEntity.type(x))([1,2,3]))
   .then((_) => futureThrows(((x, y) =>
        FileSystemEntity.type(x, followLinks: y))(".", "why not?")))
   .then((_) => futureThrows(((x, y) =>
        FileSystemEntity.identical(x, y))([1,2,3], ".")))
   .then((_) => futureThrows(((x, y) =>
        FileSystemEntity.identical(x, y))(".", 52)))
   .then((_) => futureThrows(((x) => FileSystemEntity.isLink(x))(52)))
   .then((_) => futureThrows(((x) => FileSystemEntity.isFile(x))(52)))
   .then((_) => futureThrows(((x) => FileSystemEntity.isDirectory(x))(52)))
-  .then((_) => keepAlive.close());
+  .then((_) => asyncEnd());
 }
 
 String getFilename(String path) {
   return new File(path).existsSync() ? path : 'runtime/$path';
 }
 
 main() {
   testReadInvalidArgs('asdf');
   testReadIntoInvalidArgs(12, 0, 1);
   testReadIntoInvalidArgs(new List(10), '0', 1);
   testReadIntoInvalidArgs(new List(10), 0, '1');
   testWriteByteInvalidArgs('asdf');
   testWriteFromInvalidArgs(12, 0, 1);
   testWriteFromInvalidArgs(new List(10), '0', 1);
   testWriteFromInvalidArgs(new List(10), 0, '1');
   testWriteStringInvalidArgs("Hello, world", 42);
   testFileSystemEntity();
 }