trx_t::commit_in_memory(): Do not initiate a redo log write if
the transaction has no visible effect. If anything for this
transaction had been made durable, crash recovery will roll back
the transaction just fine even if the end of ROLLBACK is not
durably written.

Rollbacks of transactions that are associated with XA identifiers
(possibly internally via the binlog) will always be persisted.
The test rpl.rpl_gtid_crash covers this.