Misc: simplify code

sql/sql_table.cc

@@ -10013,14 +10013,9 @@ copy_data_between_tables(THD *thd, TABLE *from, TABLE *to,
 
     if (make_versioned)
     {
-      to_sys_trx_start->set_notnull(to_sys_trx_start->null_offset());
-      // TODO: write directly to record bypassing the same checks on every call
+      to_sys_trx_start->set_notnull();
       to_sys_trx_start->store_time(&query_start);
-
-      static const timeval max_tv= {TIMESTAMP_MAX_VALUE, TIME_MAX_SECOND_PART};
-      static const uint dec= TIME_SECOND_PART_DIGITS;
-      to_sys_trx_end->set_notnull(to_sys_trx_end->null_offset());
-      my_timestamp_to_binary(&max_tv, to_sys_trx_end->ptr, dec);
+      to_sys_trx_end->set_max();
     }
     else if (make_unversioned)
     {