StreamContext ctor should always take a SolrClientCache

StreamExpression expression = StreamExpressionParser.parse(expr);
TupleStream stream = new CloudSolrStream(expression, factory);

SolrClientCache solrClientCache = new SolrClientCache();
StreamContext streamContext = new StreamContext();
streamContext.setSolrClientCache(solrClientCache);

stream.setStreamContext(streamContext);
List<Tuple> tuples = getTuples(stream);