MDEV-16708: fixed incorrect issuing the error

 ' Access denied; you need (at least one of) the SUPER privilege(s) for this operation
on executing SET system_variable=.... in PS mode

sql/set_var.cc

@@ -836,8 +836,8 @@ int set_var::light_check(THD *thd)
     my_error(err, MYF(0), var->name.str);
     return -1;
   }
-  if (type == OPT_GLOBAL &&
-      check_global_access(thd, PRIV_SET_GLOBAL_SYSTEM_VARIABLE))
+
+  if (type == OPT_GLOBAL && var->on_check_access_global(thd))
       return 1;
 
   if (value && value->fix_fields_if_needed_for_scalar(thd, &value))