[2.2] Changes communication between appender and forcer in batched writes

to only rely on appender ticket and force ticket, w/o even involving last
committed transaction id, which was an unncessary involvement.
Also added tests to absolutely make sure that appender waits for correct
round of force, even in the face of ticket long values wrapping around
Long.MAX_VALUE.
I think 1 ms would be better. Could you not have an appender thread try to unpark the force thread just before it is entering park? Then if no other transactions arrives the force thread would wait and delay that transaction by 100ms.