evolve: add test which shows orphan-merge resolution can result to crash It happens when there are still some revisions to evolve after evoluiton of a orphan-merge. And the reason behind crash is that `lastsolved` is not being updated and contain a wrong value which is now hidden. Next patch will fix this problem.

# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)