Fix BWC tests

Author: mayya-sharipova

server/src/main/java/org/elasticsearch/index/fielddata/IndexNumericFieldData.java

@@ -164,7 +164,8 @@ public SortField sortField(
         );
         XFieldComparatorSource longSource = comparatorSource(NumericType.LONG, missingValue, sortMode, nested);
         rewrittenSortField.setMissingValue(longSource.missingObject(missingValue, reverse));
-        rewrittenSortField.setOptimizeSortWithPoints(numericSortField.getOptimizeSortWithPoints());
+        // we don't optimize sorting on int field for old indices
+        rewrittenSortField.setOptimizeSortWithPoints(false);
         return rewrittenSortField;
     }
 

server/src/main/java/org/elasticsearch/search/searchafter/SearchAfterBuilder.java

@@ -153,7 +153,13 @@ static Object convertValueFromSortField(Object value, SortField sortField, DocVa
     private static Object convertValueFromSortType(String fieldName, SortField.Type sortType, Object value, DocValueFormat format) {
         try {
             switch (sortType) {
-                case DOC, INT:
+                case DOC:
+                    if (value instanceof Number valueNumber) {
+                        return (valueNumber).intValue();
+                    }
+                    return Integer.parseInt(value.toString());
+
+                case INT:
                     // As mixing INT and LONG sort in a single request is allowed,
                     // we may get search_after values that are larger than Integer.MAX_VALUE
                     // in this case convert them to Integer.MAX_VALUE