divergence-resolution: use last evolution date to choose p1 when merging Before this patch, we choose the minimum revision as p1 while merging the two divergent csets which had a drawback that if independent user resolve the same divergence, their final resolved cset would have different hashes (because of 'divergence_source_local' and 'divergence_source_other' extras). Now, we decide the p1 on the basis of which of the two divergent cset was rewritten more recently. This new logic removes the "different hash" problem. To save us from big output changes in the tests due to this change, I also added the second factor i.e revision_number while sorting the csets wrt dates (as date is same for all the csets in tests) to fallback to the old way of picking the revision i.e choosing the minimum rev number. And to demonstrate that now divergence resolution is independent of which side user run the `hg evolve --content-div` resolved cset id won't change, I have added a separate test file. Flag --config devel.default-date='...' is being used here to record a custom date in the obsmarkers.