i.e. to reset to the initial post-startup state

performance still isn't great unfortunately, 0.7
cycles per second before this, 2.6 after this

Change-Id: Ib9d83b70f0cf052af36a49ed5bacef295fe9ed11
Reviewed-on: https://gerrit.libreoffice.org/19269Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>