Added several unit tests for the XTitle interface.
Tests are for bugs tdf#96044,tdf#98837,tdf#96896

Change-Id: I9b3990dff02d5d5738024b60e94555199b625a2e
Reviewed-on: https://gerrit.libreoffice.org/23834Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>