[Java] ArrowVectorIterator incorrectly closes Vectors

If you’re using the iterator with reuseVectorSchemaRoot set to false, the first n-1 VSRs returned by a call to next() have their resources managed by the client code, but the last one gets closed when the iterator is closed. This is inconsistent and contradicts the  javadoc for next:

• If {@link JdbcToArrowConfig#isReuseVectorSchemaRoot()} is false,
• the client is responsible for freeing its resources.

The iterator calls close on its CompositeJDBCConsumer instance, which in turn closes the vectors held by each consumer. 

@Override
public void close() {
  if (config.isReuseVectorSchemaRoot()) {
  nextBatch.close();
    }
  compositeConsumer.close();
}