Add option to specify jsc args in run-sunspider.
https://bugs.webkit.org/show_bug.cgi?id=134341

Patch by Gergo Balogh <gbalogh.u-szeged@partner.samsung.com> on 2014-07-03
Reviewed by Csaba Osztrogonác.

* Scripts/run-sunspider:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170750 268f45cc-cd09-0410-ab3c-d52691b4dbfc