Optimized LatLon sorting does not work in the descending order.

core/src/main/java/org/elasticsearch/search/sort/GeoDistanceSortBuilder.java

@@ -558,6 +558,7 @@ public class GeoDistanceSortBuilder extends SortBuilder<GeoDistanceSortBuilder>
                 && nested == null
                 && finalSortMode == MultiValueMode.MIN // LatLonDocValuesField internally picks the closest point
                 && unit == DistanceUnit.METERS
+                && reverse == false
                 && localPoints.size() == 1) {
             return new SortFieldAndFormat(
                     LatLonDocValuesField.newDistanceSort(fieldName, localPoints.get(0).lat(), localPoints.get(0).lon()),

core/src/test/java/org/elasticsearch/search/sort/GeoDistanceSortBuilderTests.java

@@ -501,5 +501,10 @@ public class GeoDistanceSortBuilderTests extends AbstractSortTestCase<GeoDistanc
         builder.setNestedPath("some_nested_path");
         sort = builder.build(context);
         assertEquals(SortField.class, sort.field.getClass()); // can't use LatLon optimized sorting with nested fields
+
+        builder = new GeoDistanceSortBuilder("random_field_name", new GeoPoint(3.5, 2.1));
+        builder.order(SortOrder.DESC);
+        sort = builder.build(context);
+        assertEquals(SortField.class, sort.field.getClass()); // can't use LatLon optimized sorting with DESC sorting
     }
 }