Add replication crash-safety for non-GTID slave.

The way to achieve replication crash safety in MariaDB 10.0 is to enable GTID slave negotiation, but this is not always possible and comes with drawbacks:

1. 1. It is not possible to enable GTID slave negotiation when the master is not MariaDB 10.
2. 2. GTID slave negotiation put extra burden on the master.
3. 3. GTID slave negotiation does not yet works with MaxScale Binlog Servers.
4. 4. GTID slave negotiation overloads the master NIC on restarting IO_THREAD on lagging slave (MDEV-8945).

Having replication crash-safety in file/position replication with MariaDB would be useful. This does not look very hard to implement and is implemented in MySQL 5.6. See this post for more information and pitfalls in the MySQL implementation:
https://medium.com/booking-com-infrastructure/better-crash-safe-replication-for-mysql-a336a69b317f

Thanks,

JFG