Clean up the Windows watcher.

pkg/analysis_server/test/physical_resource_provider_test.dart

Index: pkg/analysis_server/test/physical_resource_provider_test.dart
diff --git a/pkg/analysis_server/test/physical_resource_provider_test.dart b/pkg/analysis_server/test/physical_resource_provider_test.dart
index e3dfdc7b68d6dcf18fdccd104a46d01c3d253357..63f0a0d484941cdc82e10ff5d2a083f93b74d52d 100644
--- a/pkg/analysis_server/test/physical_resource_provider_test.dart
+++ b/pkg/analysis_server/test/physical_resource_provider_test.dart
@@ -32,6 +32,9 @@ main() {
       group('Watch', () {
 
         Future delayed(computation()) {
+          // Give the tests 1 second to detect the changes. While it may only
+          // take up to a few hundred ms, a whole second gives a good margin
+          // for when running tests.
           return new Future.delayed(
               new Duration(seconds: 1), computation);
         }