enable ww8import/export tests for mac

Change-Id: I6b29040a2cd4ad24f18dfafb51d95d2b7627dd27
Reviewed-on: https://gerrit.libreoffice.org/10144
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>