title: ng test fails it runs firefox lib
body: <p><code>ng test fails</code> It produces a such error log.
  Why does it try firefox? Few tests ago it works well with Chrome. I can not define what I have done wrong.</p>
  
  <pre><code>ERROR in ./node_modules/selenium-webdriver/firefox/binary.js
  Module not found: Error: Can't resolve 'child_process' in '/home/marting/github/martin-eden-sailor/mw/node_modules/selenium-webdriver/firefox'
  resolve 'child_process' in '/home/marting/github/martin-eden-sailor/mw/node_modules/selenium-webdriver/firefox'
    Parsed request is a module
    using description file: /home/marting/github/martin-eden-sailor/mw/node_modules/selenium-webdriver/package.json (relative path: ./firefox)
      Field 'browser' doesn't contain a valid alias configuration
      resolve as module
        looking for modules in /home/marting/github/martin-eden-sailor/mw/
          using description file: /home/marting/github/martin-eden-sailor/mw/package.json (relative path: .)
            Field 'browser' doesn't contain a valid alias configuration
            using description file: /home/marting/github/martin-eden-sailor/mw/package.json (relative path: ./child_process)
  </code></pre>