evolve: make sure user can recover from conflict (issue6053)
we make sure while continuing interrupted evolve it reach to right code
This patch fix the issue6053 which is about falling evolve into unrecoverable
state and this is how it call fall into it:
If after some rewrite operations we reach to a point where resparent for
two content divergent csets is obsolete and we hit a conflict in
relocation, so now if you run `hg evolve --continue` after resolving
the conflict: code execution would check if wdir parent is obsolete
and run solveobswdp() rather than going to continueevolve() part
and there we will hit by a "abort: outstanding uncommitted merge"
And same for `--abort` or `--stop` flags.
Changes in tests reflect the fixed behaviour.