CppunitTest_sw_rtfimport: enable on Mac

Change-Id: I5ab812c51e24877a2ad9be29a9d411c08b3234c3
Reviewed-on: https://gerrit.libreoffice.org/9514
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>