worker: remove delete MessagePort.prototype.hasRef

Node Code+Learn: remove delete MessagePort.prototype.hasRef;

PR-URL: #23471
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>

lib/internal/worker.js

@@ -71,7 +71,6 @@ Object.setPrototypeOf(MessagePort.prototype, EventEmitter.prototype);
 // Finally, purge methods we don't want to be public.
 delete MessagePort.prototype.stop;
 delete MessagePort.prototype.drain;
-delete MessagePort.prototype.hasRef;
 MessagePort.prototype.ref = MessagePortPrototype.ref;
 MessagePort.prototype.unref = MessagePortPrototype.unref;