Checkpoint commit for OPENDJ-1206 : Create a new ReplicationBackend/ChangelogBackend 
 to support cn=changelog

Add more tests for changelog backend. Tests are still disabled (until changelog backend is
 activated in code).

ChangelogBackedTestCase.java: 
 - add new tests for cookie search : one and two suffixes cases
 - add TODOs for other test cases, mostly on psearches
 - renaming and cleanup

git-svn-id: https://svn.forgerock.org/opendj/trunk@10977 41b1ffd8-f28e-4786-ab96-9950f0a78031