Method __resetForTesting

tests/helpers/package-cache.js:253–255

* The `__resetForTesting` puts things back in module scope. * * @private * @method __resetForTesting

()

   * @method __resetForTesting
   */
  __resetForTesting() {
    commands = originals;
  }

  /**
   * The `_cleanDirs` method deals with sync issues between the