test: improve code in test-http-host-headers

* use common.fail to handle errors
* remove console.log
* use arrow functions

PR-URL: https://github.com/nodejs/node/pull/10830


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>