Merge branch '10.2' into 10.3

sql/opt_range.cc

@@ -7188,7 +7188,7 @@ SEL_TREE *Item_func_in::get_func_mm_tree(RANGE_OPT_PARAM *param,
       {
         key_map::Iterator it(field->key_start);
         uint key_no;
-        while ((key_no= it.next_bit()) != key_map::Iterator::BITMAP_END)
+        while ((key_no= it++) != key_map::Iterator::BITMAP_END)
         {
           KEY *key_info= &field->table->key_info[key_no];
           if (key_info->user_defined_key_parts == 1 &&