tests: qemuxml2argv: Validate generation of JSON props for object-add
tests: qemuxml2argv: Validate generation of JSON props for object-add

Similarly to the validation for blockdev-add and netdev_add, use the
qemuxml2argv test repository to drive validation of props for
object-add.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

libvirt/libvirt,nertpinx/libvirt,zippy2/libvirt,jfehlig/libvirt,olafhering/libvirt,nertpinx/libvirt,libvirt/libvirt,crobinso/libvirt,nertpinx/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,zippy2/libvirt,zippy2/libvirt,nertpinx/libvirt,libvirt/libvirt,nertpinx/libvirt,olafhering/libvirt,crobinso/libvirt,jfehlig/libvirt,crobinso/libvirt,olafhering/libvirt,jfehlig/libvirt,olafhering/libvirt,libvirt/libvirt