Clean up some pub and scheduled_test integration with the new isolate API.

pkg/scheduled_test/test/descriptor/file_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:io';
 
 import 'package:path/path.dart' as path;
 import 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../metatest.dart';
 import 'utils.dart';
 
-void main(List<String> args, message) {
-  metaTestInit(message);
+void main(_, message) {
+  initMetatest(message);
 
   setUpTimeout();
 
   expectTestsPass('file().create() creates a file', () {
     test('test', () {
       scheduleSandbox();
 
       d.file('name.txt', 'contents').create();
 
       schedule(() {
@@ skipping 231 matching lines @@
     });
 
     test('test 2', () {
       expect(errors.single, new isInstanceOf<ScheduleError>());
       expect(errors.single.error.toString(), equals(
           "Expected: contains <12>\n"
           "  Actual: [98, 97, 114, 102, 111, 111, 98, 97, 122]\n"));
     });
   }, passing: ['test 2']);
 }