Here, we can just initialize the iterators with the right increment
instead of using while loops to increment them

Change-Id: I08b51ba11398dbb705d3ed83bfbf46df0deb7f21
Reviewed-on: https://gerrit.libreoffice.org/47224Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>