@Override
    public boolean setReplicaStoppedState(List<ReplicaId> replicaIds, boolean markStop) {
      if (setStopStateReturnVal != null) {
        return setStopStateReturnVal;
      }
      if (markStop) {
        stoppedReplicas.addAll(replicaIds);
      } else {
        stoppedReplicas.removeAll(replicaIds);
      }
      return true;
    }
Ctor for MockClusterParticipant with arguments to override return value of some methods.
@param setSealStateReturnVal if not null, use this value to override result of setReplicaSealedState(). If null,
                             go through standard workflow in the method.
@param setStopStateReturnVal if not null, use this value to override result of setReplicaStoppedState(). If null,
                             go through standard workflow in the method.
ambry-store/src/test/java/com/github/ambry/store/StorageManagerTest.java