LUCENE-6766: don't throw exc from MultiXXX if there is an index sort

lucene/core/src/java/org/apache/lucene/index/MultiSorter.java

@@ -123,7 +123,7 @@ final class MultiSorter {
 
   private static CrossReaderComparator getComparator(List<CodecReader> readers, SortField sortField) throws IOException {
     switch(sortField.getType()) {
-    // TODO: use global ords for string sort
+    // ncommit: use segment-local ords for string sort
     case INT:
       {
         List<NumericDocValues> values = new ArrayList<>();

lucene/core/src/java/org/apache/lucene/search/IndexSearcher.java

@@ -819,6 +819,7 @@ public class IndexSearcher {
       sumTotalTermFreq = terms.getSumTotalTermFreq();
       sumDocFreq = terms.getSumDocFreq();
     }
+
     return new CollectionStatistics(field, reader.maxDoc(), docCount, sumTotalTermFreq, sumDocFreq);
   }
 }