Code cleanup:
- hid ReplicationDomain internals
- moved test code out of production code
- removed duplicated test code


ReplicationDomain.java:
In ctor, delegate to other ctor.
In startPublishService(), removed ReplicationDomainCfg parameter and get the config from field instead.
Removed getConfig(), not used anymore.
Moved publish(byte[]) to ReplicationDomainTest.

LDAPReplicationDomain.java, AssuredReplicationServerTest.java, FakeStressReplicationDomain.java:
Consequence of the change to ReplicationDomain.startPublishService().


FakeReplicationDomain.java:
Expanded the code to support what FractionalReplicationTest.FakeReplicationDomain was doing.
Consequence of the change to ReplicationDomain.startPublishService().

FractionalReplicationTest.java:
Removed FakeReplicationDomain inner class, replaced by org.opends.server.replication.service.FakeReplicationDomain.
Removed newConfig(), now unused.

ReplicationDomainTest.java:
Moved ReplicationDomain.publish(byte[]) here.
Extracted method publishRepeatedly().