evolve: add tests which shows evolve can get confused about copies (issue5930)
This test demonstrate that an interrupted evolve can get confused about
copies. Next patch will fix this.
split: use ui.configoverride to preserve phase while commiting
As we need to preserve the phase of revision which is going to be
splitted into multiple revision. This patch use ui.configoverrides
to temporarily overwrite the phases.new-commit config option at the
time of committing a new node.