test: allow passing args to executable

Add --node-args option that will pass arguments.

PR-URL: https://github.com/nodejs/node/pull/5376


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>