MDEV-25530 Error 1451 on slave: Cannot delete or update a parent row: a foreign key constraint fails

after dfb41fdd tables that failed to drop are excluded from the
binlogged DROP TABLE statement. It means that the slave should not
expect any errors when executing DROP TABLE, and the binlog should
report that no error has happened, even if it was.

Do not write error code into the binlogged DROP TABLE,
and remove all code that was needed to compute it.