src: honor --abort_on_uncaught_exception flag

Fix regression introduced in 0af4c9ea
that ignores the --abort-on-uncaught-exception flag. Prior to that
commit, the flag was passed through to v8. After that commit, the
process just calls exit(1).

PR-URL: https://github.com/nodejs/node/pull/2776


Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-by: Trevor Norris <trev.norris@gmail.com>