Functions MINIFS and MAXIFS

Change-Id: I4bd2e8b82f8377af81f4373d0c33ac286588b8df
Reviewed-on: https://gerrit.libreoffice.org/24619Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>