test: fix flaky test-worker-message-port-transfer-filehandle test

PR-URL: #59158
Fixes: #59145
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Stefan Stojanovic <stefan.stojanovic@janeasystems.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: himself65

test/parallel/test-worker-message-port-transfer-filehandle.js

@@ -86,6 +86,7 @@ const { once } = require('events');
   });
 
   assert.deepStrictEqual(await readPromise, await fs.readFile(__filename));
+  await fh.close();
 })().then(common.mustCall());
 
 (async function() {