test: include port in assertion message

PR-URL: #20889
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-net-listen-exclusive-random-ports.js

@@ -9,11 +9,13 @@ if (cluster.isMaster) {
   const worker1 = cluster.fork();
 
   worker1.on('message', function(port1) {
-    assert.strictEqual(port1, port1 | 0, 'first worker could not listen');
+    assert.strictEqual(port1, port1 | 0,
+                       `first worker could not listen on port ${port1}`);
     const worker2 = cluster.fork();
 
     worker2.on('message', function(port2) {
-      assert.strictEqual(port2, port2 | 0, 'second worker could not listen');
+      assert.strictEqual(port2, port2 | 0,
+                         `second worker could not listen on port ${port2}`);
       assert.notStrictEqual(port1, port2, 'ports should not be equal');
       worker1.kill();
       worker2.kill();