Revert "MDEV-13115: SKIP LOCKED postfix"

This reverts commit 51630d59.

Monty has more comprehensive fix coming in his branch.

sql/sql_lex.h

@@ -1295,13 +1295,13 @@ class st_select_lex: public st_select_lex_node
   bool exclude_from_table_unique_test;
   /* the select is "service-select" and can not have tables*/
   bool is_service_select;
+  /* index in the select list of the expression currently being fixed */
+  int cur_pos_in_select_list;
+
   /* SELECT [FOR UPDATE/LOCK IN SHARE MODE] [SKIP LOCKED] */
-  bool skip_locked;
   enum select_lock_type {NONE, IN_SHARE_MODE, FOR_UPDATE};
   enum select_lock_type select_lock;
-
-  /* index in the select list of the expression currently being fixed */
-  int cur_pos_in_select_list;
+  bool skip_locked;
 
   List<udf_func>     udf_list;                  /* udf function calls stack */