OPENDJ-1453 (CR-3938) Replica offline messages should be synced with updates

This changed managed to solve the combined DS/RS case. Mostly, because robot test is sometimes failing yet.
This is fixed by introducing a DSRSShutdownSync class which ensures that when the DS sends a ReplicaOfflineMsg, the RS will relay it to the rest of the topology.
Second main change is to ensure ReplicaOfflineMsgs do not update the domain's ServerState otherwise the functional tests detect an inconsistency in the backend ds-sync-state data between the 2 replica: the one that is stopped and the one that is never stopped. For this I added UpdateMsg.contributesToDomainState() and used it throughout.
The rest of the change is passing the DSRSShutdownSync down method calls.



DSRSShutdownSync.java: ADDED

UpdateMsg.java, ReplicaOfflineMsg.java:
Added contributesToDomainState()



MultimasterReplication.java:
Added dsrsShutdownSync field + created it here + passed it down creation of LDAPReplicationDomain and ReplicationServerListener.
Code cleanup.

LDAPReplicationDomain.java:
Added dsrsShutdownSync field + used it in publishReplicaOfflineMsg().

ReplicationServerListener.java
Added dsrsShutdownSync field + used it when creating ReplicationServer.
Code cleanup.

ReplicationServer.java:
Added dsrsShutdownSync field + added getDSRSShutdownSync() getter.

ServerHandler.java
Called ReplicationServer.getDSRSShutdownSync() when creating ServerWriter.
Code cleanup.

ServerWriter.java:
Added dsrsShutdownSync field + used it in run().



ECLServerWriter.java:
Consequence of the change to ServerWriter.
Code cleanup.



RemotePendingChanges.java, ReplicationDomain.java, MessageHandler.java:
Used UpdateMsg.contributesToDomainState().