streams: implement streams to webstreams adapters

Experimental adapters for the webstreams API

Signed-off-by: James M Snell <jasnell@gmail.com>

Author: jasnell

lib/internal/fs/promises.js

@@ -790,6 +790,8 @@ module.exports = {
     appendFile,
     readFile,
     watch,
+
+    kHandle,
   },
 
   FileHandle,