Allow more time for tests on Windows.

Author: davidmorgan

pkgs/watcher/test/directory_watcher/windows_test.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 @TestOn('windows')
+@Timeout.factor(2)
 library;
 
 import 'dart:async';