Native pass-through queries combined with other conditions might not work

Native pass-through queries as defined in OAK-1325 might not work correctly (depending on the cost of the index implementation) if the native condition is combined with other (for example property-) conditions.

The problem is that indexes that are not applicable (property indexes and the traversing index) don't check if there is a native condition, and therefore might return a lower cost than the appropriate (Solr or Lucene) index.

Currently this might not be a problem, because the Solr index returns a low cost for native queries. However, in the future this might no longer be the case once the cost function of the Solr index is changed.