Remove preload options in TestWorker

This doesn’t serve any purpose. We call `runTest` in workers right after we were calling these preload methods which implicitly called the the preload methods themselves.

src/TestRunner.js

@@ -206,36 +206,6 @@ class TestRunner {
       });
   }
 
-  /**
-   * For use by external users of TestRunner as a means of optimization.
-   *
-   * Imagine the following scenario executing in a child worker process:
-   *
-   * var runner = new TestRunner(config, {
-   *   moduleLoaderResourceMap: serializedResourceMap
-   * });
-   * someOtherAyncProcess.then(function() {
-   *   runner.runTestsParallel();
-   * });
-   *
-   * Here we wouldn't start deserializing the resource map (passed to us from
-   * the parent) until runner.runTestsParallel() is called. At the time of this
-   * writing, resource map deserialization is slow and a bottleneck on running
-   * the first test in a child.
-   *
-   * So this API gives scenarios such as the one above an optimization path to
-   * potentially start deserializing the resource map while we wait on the
-   * someOtherAsyncProcess to resolve (rather that doing it after it's
-   * resolved).
-   */
-  preloadResourceMap() {
-    this._getModuleLoaderResourceMap().then(null, promiseDone);
-  }
-
-  preloadConfigDependencies() {
-    this._loadConfigDependencies();
-  }
-
   /**
    * Run the given single test file path.
    * This just contains logic for running a single test given it's file path.

src/TestWorker.js

@@ -8,9 +8,7 @@
 'use strict';
 
 // Make sure uncaught errors are logged before we exit.
-// Could be transient errors to do with loading and serializing the resouce
-// map.
-process.on('uncaughtException', (err) => {
+process.on('uncaughtException', err => {
   console.error(err.stack);
   process.exit(1);
 });
@@ -19,30 +17,11 @@ const TestRunner = require('./TestRunner');
 
 let testRunner;
 
-module.exports = function testWorker(data, callback) {
+module.exports = (data, callback) => {
   if (!testRunner) {
     testRunner = new TestRunner(data.config, {
       useCachedModuleLoaderResourceMap: true,
     });
-
-    // Start require()ing config dependencies now.
-    //
-    // Config dependencies are entries in the config that are require()d (in
-    // order to be pluggable) such as 'moduleLoader' or
-    // 'testEnvironment'.
-    testRunner.preloadConfigDependencies();
-
-    // Start deserializing the resource map to get a potential head-start on
-    // that work before the first "run-test" message comes in.
-    //
-    // This is just a perf optimization -- and it is only an optimization
-    // some of the time (when the there is any significant idle time between
-    // this first initialization message and the first "run-rest" message).
-    //
-    // It is also only an optimization so long as deserialization of the
-    // resource map is a bottleneck (which is the case at the time of this
-    // writing).
-    testRunner.preloadResourceMap();
   }
 
   try {