Use 'Directory.watch' on Windows in pkg/watcher, instead of pooling.

pkg/pkg.status

Index: pkg/pkg.status
diff --git a/pkg/pkg.status b/pkg/pkg.status
index d129feb4abf8b7e9d4dfb681f302703f7ee9acc8..39a275ca1c216e5566c2c9463075af62d3537055 100644
--- a/pkg/pkg.status
+++ b/pkg/pkg.status
@@ -365,6 +365,9 @@ watcher/test/*/linux_test: Skip
 [ $runtime == vm && ($system == windows || $system == linux) ]
 watcher/test/*/mac_os_test: Skip
 
+[ $runtime == vm && ($system == macos || $system == linux) ]
+watcher/test/*/windows_test: Skip
+
 [ $runtime == safari || $runtime == safarimobilesim || $runtime == chrome || $runtime == ff || $ie ]
 # Various issues due to limited browser testing in Angular.
 third_party/angular_tests/*: Skip