[GTK] Disable the unit tests timeout when running from make check
https://bugs.webkit.org/show_bug.cgi?id=106670

Patch by Carlos Garcia Campos <cgarcia@igalia.com> on 2013-01-11
Reviewed by Philippe Normand.

* GNUmakefile.am: Pass --timeout=-1 to run-gtk-test.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@139453 268f45cc-cd09-0410-ab3c-d52691b4dbfc