Updated the files.

my-app/node_modules/jest-worker/build/workers/messageParent.js

@@ -0,0 +1,38 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', {
+  value: true
+});
+exports.default = messageParent;
+
+var _types = require('../types');
+
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+const isWorkerThread = (() => {
+  try {
+    // `Require` here to support Node v10
+    const {isMainThread, parentPort} = require('worker_threads');
+
+    return !isMainThread && parentPort != null;
+  } catch {
+    return false;
+  }
+})();
+
+function messageParent(message, parentProcess = process) {
+  if (isWorkerThread) {
+    // `Require` here to support Node v10
+    const {parentPort} = require('worker_threads'); // ! is safe due to `null` check in `isWorkerThread`
+
+    parentPort.postMessage([_types.PARENT_MESSAGE_CUSTOM, message]);
+  } else if (typeof parentProcess.send === 'function') {
+    parentProcess.send([_types.PARENT_MESSAGE_CUSTOM, message]);
+  } else {
+    throw new Error('"messageParent" can only be used inside a worker');
+  }
+}