removed artifacts from invalid shape: nested shape instruction destination 
now is not drawn on its own. instead it is merged with outer shape 
instruction. this helps to avoid drawing semi-ready shapes.

Change-Id: I45589cc1b742d878e5914dd3f66a8184ecfd044c
Reviewed-on: https://gerrit.libreoffice.org/14584Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>