loadAsScript(name, {referrerName, address, metadata = {}} = {}) {
    metadata.traceurOptions = metadata.traceurOptions || {};
    metadata.traceurOptions.script = true;
    return this.internalLoader_.load(name, referrerName, address, metadata).
        then((load) => load.result);
  }
See https://github.com/jorendorff/js-loaders/issues/92
loadAsScript - Asynchronously load and run a script. If the script
calls Loader.import(),  this can cause modules to be loaded, linked,
and evaluated.

This function is the same as import(), with one exception: the text of
the initial load is parsed to goal 'Script' rather than 'Module'

@param {string} name, relative path to js file.
@param {Object} referrerName and address passed to normalize.
@return {Promise} fulfilled with evaluation result.