WFLY-3766: reworking ejb calendar based timeout logic and tests to ensur...

...e propert dst changes handling
that particular use case is when the nextCal computed is equal on both timezones (with and without dst changes), i.e. nextCal is on STD, and either:
   - currentCal is on DST
   - nextCal is in DST rollback period

In concrete what that means is that either we are in the period that will be repeated (DST), or in the repeated period (STD), but we need to guess which, and the current cal DST offset gives us the answer.

Note that the transition between DST and STD periods is handled by the other branch of the if (line 327), when the currentCal is on DST and nextCal is after the DST rollback period, we go back to when STD starts (the repeated period).