evolve: remove tmpctx arg from _resolvephasedivergent()
Before this patch, in _resolvephasedivergent() function we were passing
an optional argument "tmpctx" which was used to store a rebased version
of bumped if required. But for sake of simplicity we can achieve the
same results even without passing this "tmpctx" into that function.
No changes in test files demonstrate that this patch don't break
anything.