MDEV-33726 Moving from MariaDB 10.5 to 10.6 mysql_upgrade

.. is not updating some system tables

Some schema changes from MDEV-24312 master_host has 60 character limit, increase to 255 bytes
failed to happen in the upgrade for tables in the mysql schema:
* mysql.global_priv
* mysql.procs_priv
* mysql.proxies_priv
* mysql.roles_mapping

mysql-test/main/system_mysql_db_fix50030.result

@@ -151,7 +151,7 @@ columns_priv	CREATE TABLE `columns_priv` (
 show create table procs_priv;
 Table	Create Table
 procs_priv	CREATE TABLE `procs_priv` (
-  `Host` char(60) NOT NULL DEFAULT '',
+  `Host` char(255) NOT NULL DEFAULT '',
   `Db` char(64) NOT NULL DEFAULT '',
   `User` char(128) NOT NULL DEFAULT '',
   `Routine_name` char(64) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL DEFAULT '',

mysql-test/main/system_mysql_db_fix50117.result

@@ -131,7 +131,7 @@ columns_priv	CREATE TABLE `columns_priv` (
 show create table procs_priv;
 Table	Create Table
 procs_priv	CREATE TABLE `procs_priv` (
-  `Host` char(60) NOT NULL DEFAULT '',
+  `Host` char(255) NOT NULL DEFAULT '',
   `Db` char(64) NOT NULL DEFAULT '',
   `User` char(128) NOT NULL DEFAULT '',
   `Routine_name` char(64) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL DEFAULT '',

mysql-test/main/system_mysql_db_fix50568.result

@@ -152,7 +152,7 @@ columns_priv	CREATE TABLE `columns_priv` (
 show create table procs_priv;
 Table	Create Table
 procs_priv	CREATE TABLE `procs_priv` (
-  `Host` char(60) NOT NULL DEFAULT '',
+  `Host` char(255) NOT NULL DEFAULT '',
   `Db` char(64) NOT NULL DEFAULT '',
   `User` char(128) NOT NULL DEFAULT '',
   `Routine_name` char(64) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL DEFAULT '',

scripts/mysql_system_tables_fix.sql

@@ -762,19 +762,22 @@ if @have_innodb then
 end if //
 DELIMITER ;
 
-# MDEV-4332 longer user names
+# MDEV-4332 longer user names, extended by MDEV-24312 to longer again.
 alter table user         modify User         char(128)  binary not null default '';
 alter table db           modify User         char(128)  binary not null default '';
 alter table tables_priv  modify User         char(128)  binary not null default '';
 alter table columns_priv modify User         char(128)  binary not null default '';
-alter table procs_priv   modify User         char(128)  binary not null default '';
+alter table procs_priv   modify User         char(128)  binary not null default '', modify Host char(255) binary DEFAULT '';
 alter table proc         modify definer      varchar(384) collate utf8mb3_bin not null default '';
-alter table proxies_priv modify User         char(128)  COLLATE utf8mb3_bin not null default '';
+alter table proxies_priv modify User         char(128)  COLLATE utf8mb3_bin not null default '', modify Host char(255) binary DEFAULT '';
 alter table proxies_priv modify Proxied_user char(128)  COLLATE utf8mb3_bin not null default '';
 alter table proxies_priv modify Grantor      varchar(384) COLLATE utf8mb3_bin not null default '';
 alter table servers      modify Username     char(128)                   not null default '';
 alter table procs_priv   modify Grantor      varchar(384) COLLATE utf8mb3_bin not null default '';
 alter table tables_priv  modify Grantor      varchar(384) COLLATE utf8mb3_bin not null default '';
+# MDEV-33726 longer names from MDEV-24312 extension
+alter table if exists global_priv modify Host char(255) binary DEFAULT '', modify User char(128)  binary not null default '';
+alter table if exists roles_mapping modify Host char(255) binary not null DEFAULT '', modify User char(128)  binary not null default '';
 
 # Activate the new, possible modified privilege tables
 # This should not be needed, but gives us some extra testing that the above