MDEV-32144 fixup

In commit 384eb570 the debug check
was relaxed in trx_undo_header_create(), not in the intended function
trx_undo_write_xid().

storage/innobase/trx/trx0undo.cc

@@ -523,8 +523,9 @@ static void trx_undo_write_xid(buf_block_t *block, uint16_t offset,
                                  static_cast<uint32_t>(xid.bqual_length));
   const ulint xid_length= static_cast<ulint>(xid.gtrid_length
                                              + xid.bqual_length);
-  mtr->memcpy(*block, &block->frame[offset + TRX_UNDO_XA_XID],
-              xid.data, xid_length);
+  mtr->memcpy<mtr_t::MAYBE_NOP>(*block,
+                                &block->frame[offset + TRX_UNDO_XA_XID],
+                                xid.data, xid_length);
   if (UNIV_LIKELY(xid_length < XIDDATASIZE))
     mtr->memset(block, offset + TRX_UNDO_XA_XID + xid_length,
                 XIDDATASIZE - xid_length, 0);