Fix file-system-entity watching on Windows.

runtime/bin/file_patch.dart

Index: runtime/bin/file_patch.dart
diff --git a/runtime/bin/file_patch.dart b/runtime/bin/file_patch.dart
index dccf138b1bfde297f949189317cb0794a50dc10c..4b5e5e6f0d45118b29ca34eab2643e1dbaf7f467 100644
--- a/runtime/bin/file_patch.dart
+++ b/runtime/bin/file_patch.dart
@@ -92,7 +92,7 @@ class _FileSystemWatcherImpl
         bool getIsDir(event) {
           if (Platform.isWindows) {
             // Windows does not get 'isDir' as part of the event.
-            return FileSystemEntity.isDirectorySync(path);
+            return FileSystemEntity.isDirectorySync(getPath(event));
           }
           return (event[0] & FileSystemEvent._IS_DIR) != 0;
         }