MDEV-18241 Downgrade from 10.4 to 10.3 crashes

privilege tables can never be views or temporary tables,
don't even try to open them, if they are.

mysql-test/r/grant4.result

@@ -121,3 +121,14 @@ View	Create View	character_set_client	collation_connection
 v3	CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER VIEW `v3` AS select `t_select_priv`.`a` AS `a`,`t_select_priv`.`b` AS `b` from `t_select_priv`	latin1	latin1_swedish_ci
 drop database mysqltest_db1;
 drop user mysqltest_u1@localhost;
+call mtr.add_suppression("Table 'mysql.user' doesn't exist");
+rename table mysql.user to mysql.user1;
+create view mysql.user as select * from mysql.user1;
+flush privileges;
+ERROR 42S02: Table 'mysql.user' doesn't exist
+drop view mysql.user;
+create temporary table mysql.user select * from mysql.user1 limit 0;
+flush privileges;
+ERROR 42S02: Table 'mysql.user' doesn't exist
+drop temporary table mysql.user;
+rename table mysql.user1 to mysql.user;

mysql-test/t/grant4.test

@@ -144,3 +144,18 @@ connection default;
 disconnect con1;
 drop database mysqltest_db1;
 drop user mysqltest_u1@localhost;
+
+#
+# MDEV-18241 Downgrade from 10.4 to 10.3 crashes
+#
+call mtr.add_suppression("Table 'mysql.user' doesn't exist");
+rename table mysql.user to mysql.user1;
+create view mysql.user as select * from mysql.user1;
+--error ER_NO_SUCH_TABLE
+flush privileges;
+drop view mysql.user;
+create temporary table mysql.user select * from mysql.user1 limit 0;
+--error ER_NO_SUCH_TABLE
+flush privileges;
+drop temporary table mysql.user;
+rename table mysql.user1 to mysql.user;

sql/sql_acl.cc

@@ -1155,8 +1155,12 @@ static void fix_table_list(TABLE_LIST *tl, uint n)
   TABLE_LIST *end;
   for (end= tl + n - 1; tl < end; tl++)
   {
+    tl->i_s_requested_object= OPEN_TABLE_ONLY;
+    tl->open_type= OT_BASE_ONLY;
     tl->next_local= tl->next_global= tl + 1;
   }
+  tl->i_s_requested_object= OPEN_TABLE_ONLY;
+  tl->open_type= OT_BASE_ONLY;
 }