MDEV-24652 mtr fails while reusing the cached undo log block

While reusing the cached undo log block, mtr expects the page
write to change while writing the trx id. cached undo log block
could contain bytes which were originally written for some other
transaction. So InnoDB should make mtr to do MAYBE_NOP while reusing
cached undo log block.

Reviewed-by: Marko Mäkelä

storage/innobase/trx/trx0undo.cc

 /*****************************************************************************
 
 Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2014, 2020, MariaDB Corporation.
+Copyright (c) 2014, 2021, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -463,7 +463,8 @@ static uint16_t trx_undo_header_create(buf_block_t *undo_page, trx_id_t trx_id,
   if (prev_log)
     mtr->write<2>(*undo_page, prev_log + TRX_UNDO_NEXT_LOG + undo_page->frame,
                   free);
-  mtr->write<8>(*undo_page, free + TRX_UNDO_TRX_ID + undo_page->frame, trx_id);
+  mtr->write<8,mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_TRX_ID +
+                                 undo_page->frame, trx_id);
   /* Write TRX_UNDO_NEEDS_PURGE=1 and TRX_UNDO_LOG_START. */
   mach_write_to_2(buf, 1);
   memcpy_aligned<2>(buf + 2, start, 2);