test: add fs.watchFile() + worker.terminate() test

Refs: #21093 (comment)

PR-URL: #21179
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: addaleax

test/parallel/test-worker-fs-stat-watcher.js

@@ -0,0 +1,18 @@
+// Flags: --experimental-worker
+'use strict';
+const common = require('../common');
+const { Worker, parentPort } = require('worker_threads');
+const fs = require('fs');
+
+// Checks that terminating Workers does not crash the process if fs.watchFile()
+// has active handles.
+
+// Do not use isMainThread so that this test itself can be run inside a Worker.
+if (!process.env.HAS_STARTED_WORKER) {
+  process.env.HAS_STARTED_WORKER = 1;
+  const worker = new Worker(__filename);
+  worker.on('message', common.mustCall(() => worker.terminate()));
+} else {
+  fs.watchFile(__filename, () => {});
+  parentPort.postMessage('running');
+}