fdo#72148 if expecting table at begin, explicitly set it so

Change-Id: Ic876603e5860b987280b73726fd79a071a9c833c
Reviewed-on: https://gerrit.libreoffice.org/6865
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
Reviewed-by: Eike Rathke <erack@redhat.com>
Reviewed-by: Michael Stahl <mstahl@redhat.com>