Valdiation of LINK objects doesn't work

[J3173]

Validation of LINK objects doesn't work correctly. As LINK isn't LOCATABLE, the validator can't find LINK objects by querying on the archetype_node_id.

Example:

        links existence matches {1} matches {
            LINK[id2] occurrences matches {1} matches {    -- Some link
                ...
            }
        }

This always results in a occurrences mismatch error, even if the link exists.