Delete a bunch of packages that are now on GitHub.

pkg/watcher/test/directory_watcher/polling_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 'package:scheduled_test/scheduled_test.dart';
-import 'package:watcher/watcher.dart';
-
-import 'shared.dart';
-import '../utils.dart';
-
-void main() {
-  initConfig();
-
-  // Use a short delay to make the tests run quickly.
-  watcherFactory = (dir) => new PollingDirectoryWatcher(dir,
-      pollingDelay: new Duration(milliseconds: 100));
-
-  setUp(createSandbox);
-
-  sharedTests();
-
-  test('does not notify if the modification time did not change', () {
-    writeFile("a.txt", contents: "before");
-    writeFile("b.txt", contents: "before");
-    startWatcher();
-    writeFile("a.txt", contents: "after", updateModified: false);
-    writeFile("b.txt", contents: "after");
-    expectModifyEvent("b.txt");
-  });
-}