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

Look at the status of the `MessagePort` rather than
relying on a timeout.

PR-URL: #22658
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: addaleax

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

@@ -3,6 +3,7 @@
 
 const common = require('../common');
 const assert = require('assert');
+const util = require('util');
 const { MessageChannel } = require('worker_threads');
 
 const { port1, port2 } = new MessageChannel();
@@ -25,9 +26,22 @@ assert.throws(common.mustCall(() => {
 // The failed transfer should not affect the ports in anyway.
 port2.onmessage = common.mustCall((message) => {
   assert.strictEqual(message, 2);
+
+  assert(util.inspect(port1).includes('active: true'), util.inspect(port1));
+  assert(util.inspect(port2).includes('active: true'), util.inspect(port2));
+
   port1.close();
 
-  setTimeout(common.mustNotCall('The communication channel is still open'),
-             common.platformTimeout(1000)).unref();
+  tick(10, () => {
+    assert(util.inspect(port1).includes('active: false'), util.inspect(port1));
+    assert(util.inspect(port2).includes('active: false'), util.inspect(port2));
+  });
 });
 port1.postMessage(2);
+
+function tick(n, cb) {
+  if (n > 0)
+    setImmediate(() => tick(n - 1, cb));
+  else
+    cb();
+}