runner: Converting ArrayList to Array

Change-Id: Ifd5fe63cb00dd5b3987035201554731075d3bc00
Reviewed-on: https://gerrit.libreoffice.org/11755
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>