SolrQueryIndex blindly executes a 2nd query to check there are no more results

SolrQueryIndex#loadDocs doesn't take into account Solr's SolrDocumentList#getNumFound value to check if another query to get further results when the doc queue is empty is needed and blindly executes a second query.
This is obviously wrong as it wastes time and resources doing an unneeded query to Solr.