Move XNamed Java tests to C++ for ScDDELinkObj and refactor class
XNamed. ScDDELinkObj doesn't allow to set the name, so test that a
exception of type RuntimeException is thrown.

Change-Id: Ie110c3c0ea22d205d4f2c4575f3db3676dda9ce3
Reviewed-on: https://gerrit.libreoffice.org/64497
Tested-by: Jenkins
Reviewed-by: Jens Carl <j.carl43@gmx.de>