Alter execution of TestTestgresCommon::test_replication_slots one port is not released.

Not released port is allocated in NodeBackup::spawn_primary that is called in NodeBackup::spawn_replica:

NodeBackup::spawn_replica uses clean_on_error to destroy newly created node but clean_on_error does not call PostgresNode::free_port.

It seems to me, to fix this issue we can just call node.free_port method in clean_on_error immediatelly after node.cleanup.

Or we must to call node.free_port from node.cleanup.