the core lib has grown sufficiently large that the fuzzing tooling
complains of too many instrumented conditions so split things
up to hopefully fit again

Change-Id: I58899d143925f958aec95b5f213c2dc75a6686ec
Reviewed-on: https://gerrit.libreoffice.org/38647Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>