Prevent bundling of Node polyfills when importing TestUtils/TestRenderer (#15305)

Author: gaearon

packages/shared/enqueueTask.js

@@ -12,10 +12,13 @@ import warningWithoutStack from './warningWithoutStack';
 let didWarnAboutMessageChannel = false;
 let enqueueTask;
 try {
+  // read require off the module object to get around the bundlers.
+  // we don't want them to detect a require and bundle a Node polyfill.
+  let requireString = ('require' + Math.random()).slice(0, 7);
+  let nodeRequire = module && module[requireString];
   // assuming we're in node, let's try to get node's
-  // version of setImmediate, bypassing fake timers if any
-  let r = require; // trick packagers not to bundle this stuff.
-  enqueueTask = r('timers').setImmediate;
+  // version of setImmediate, bypassing fake timers if any.
+  enqueueTask = nodeRequire('timers').setImmediate;
 } catch (_err) {
   // we're in a browser
   // we can't use regular timers because they may still be faked