Add test for disk balance during replace
Add test for disk balance during replace

stef1927/cassandra-dtest,pcmanus/cassandra-dtest,stef1927/cassandra-dtest,bdeggleston/cassandra-dtest,snazy/cassandra-dtest,aweisberg/cassandra-dtest,beobal/cassandra-dtest,iamaleksey/cassandra-dtest,snazy/cassandra-dtest,beobal/cassandra-dtest,pauloricardomg/cassandra-dtest,blerer/cassandra-dtest,bdeggleston/cassandra-dtest,pauloricardomg/cassandra-dtest,blerer/cassandra-dtest,iamaleksey/cassandra-dtest,aweisberg/cassandra-dtest