Handle null bits for record comparison in row events the same way as in
handler::calculate_checksum(), forcing bits that can be undefined to 1.
These bits are the trailing unused bits, as well as the first bit for
tables not using HA_OPTION_PACK_RECORD.
The csv storage engine leaves these bits at 0, while the row-based
replication has them set to 1, which otherwise cause can't find record error.
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
