title: Babel with es2015 presets breaks on IE9
body: <p>I am trying my project out on IE9, but I keeps having a Exception <code>SCRIPT1010: Expected identifier</code> on the following line:</p>
  
  <p><code>
  function _interopRequireDefault(obj) { return obj &amp;&amp; obj.__esModule ? obj : { default: obj }; }
  </code></p>
  
  <p>I think it's because <code>default</code> is not wrapping in quotes.</p>
  
  <p>Just don't know where is this coming from</p>
  
  <p>I am using the following settings for Babel in webpack:</p>
  
  <p><code>
  babel: {
    presets: ['es2015'],
    plugins: ['transform-runtime', 'add-module-exports']
  }
  </code></p>
  
  <p>And following package version:</p>
  
  <p><code>
  "babel-core": "6.18.2",
  "babel-loader": "6.2.8",
  "babel-plugin-add-module-exports": "^0.2.1",
  "babel-plugin-check-es2015-constants": "6.8.0",
  "babel-plugin-transform-runtime": "6.15.0",
  "babel-polyfill": "6.16.0",
  "babel-preset-es2015": "6.18.0",
  "babel-runtime": "6.18.0",
  </code></p>