MDEV-24395 Atomic DROP TRIGGER

The purpose of this task is to ensure that DROP TRIGGER is atomic.

Description of how atomic drop trigger works:

Logging of DROP TRIGGER
    Log the following information:
    db
    table name
    trigger name
    xid /* Used to check if query was already logged to binary log */
    initial length of the .TRG file
    query if there is space for it, if not log a zero length query.

Recovery operations:
- Delete if exists 'database/trigger_name.TRN~'
  - If this file existed, it means that we crashed before the trigger
    was deleted and there is nothing else to do.
- Get length of .TRG file
  - If file length is unchanged, trigger was not dropped. Nothing else to
    do.
- Log original query to binary, if it was stored in the ddl log. If it was
  not stored (long query string), log the following query to binary log:
  use `database` ; DROP TRIGGER IF EXISTS `trigger_name`
  /* generated by ddl log */;

Other things:
- Added trigger name and DDL_LOG_STATE to drop_trigger()
  Trigger name was added to make the interface more consistent and
  more general.

sql/ddl_log.h

@@ -81,6 +81,7 @@ enum ddl_log_action_code
   DDL_LOG_DROP_TABLE_ACTION= 8,
   DDL_LOG_DROP_VIEW_INIT_ACTION= 9,
   DDL_LOG_DROP_VIEW_ACTION= 10,
+  DDL_LOG_DROP_TRIGGER_ACTION= 11,
   DDL_LOG_LAST_ACTION                          /* End marker */
 };
 
@@ -228,5 +229,10 @@ bool ddl_log_drop_view(THD *thd, DDL_LOG_STATE *ddl_state,
                         const LEX_CSTRING *path,
                         const LEX_CSTRING *db,
                         const LEX_CSTRING *table);
+bool ddl_log_drop_trigger(THD *thd, DDL_LOG_STATE *ddl_state,
+                          const LEX_CSTRING *db,
+                          const LEX_CSTRING *table,
+                          const LEX_CSTRING *trigger_name,
+                          const LEX_CSTRING *query);
 extern mysql_mutex_t LOCK_gdl;
 #endif /* DDL_LOG_INCLUDED */