evolve: add test for the case where public divergence on difference parents
This test make sure that public divergence resolution also handle the case when
divergentes changeset does not share the same parent at one end because one end
simply rebase. The other side has actual an actual diff change.
For now this would work only for the case when we need to relocate
the mutable one. Other case is still left to work on.
evolve: update the public divergence resolution logic to cover --continue case
To continue the interrupted evolve in case of public divergence:
we will have to store the node of that public cset which was in
content divergence with the other cset, so that we can perform the
phase divergence resolution between that public cset and a newnode
which is the result of content-divergence resolution.
Added tests reflect the behaviour this patch adds.