Test that leads to a tailer accessing discarded message ID.

It can happen that the oldest Message is discarded somewhere between obtaining its ID and asking for a message range, e.g. here https://github.com/triceo/splitlog/blob/383e111309aba9480f284177efbcb8e514b7ae68/splitlog-core/src/main/java/com/github/triceo/splitlog/DefaultLogWatch.java#L75-L89.

I suggest dropping the max(tailer_start_id, first_message_id) logic and always ask for the Tailer start ID. If the requested start ID is obsolete, MessageStore would produce an entry informing how many Messages were discarded.