Fixed unlikely assert/crash if initialization of translog failed

This was noticed as part of verifying MDEV-28186 "crash on startup after crash while regular use" but is probably not related to the users issue. Still good to have it fixed

Author: montywi

storage/maria/ma_loghandler.c

@@ -8936,20 +8936,23 @@ void translog_hard_group_commit(my_bool mode)
 
 void translog_sync()
 {
- uint32 max= get_current_logfile()->number;
- uint32 min;
  DBUG_ENTER("ma_translog_sync");
 
- min= soft_sync_min;
- if (!min)
- min= max;
+ /* The following is only true if initalization of translog succeded */
+ if (log_descriptor.open_files.elements != 0)
+ {
+ uint32 max= get_current_logfile()->number;
+ uint32 min;
 
- translog_sync_files(min, max, sync_log_dir >= TRANSLOG_SYNC_DIR_ALWAYS);
+ min= soft_sync_min;
+ if (!min)
+ min= max;
 
+ translog_sync_files(min, max, sync_log_dir >= TRANSLOG_SYNC_DIR_ALWAYS);
+ }
  DBUG_VOID_RETURN;
 }
 
-
 /**
  @brief set rate for group commit