histedit: test that an aborted histedit can be rerun (with obsolete) In the future, this should help catching issue as the one introduced in 6f0b7475cf9a.

histedit: backout changeset 6f0b7475cf9a Before 6f0b7475cf9a, histedit (like rebase) was only creating markers on final success from the old-rewritten node to the newly created nodes (as of before 6f0b7475cf9a). In case of abort the aborted attempt were stripped to restore the repository in its state prior to the attempt. This use of strip was on purpose. Using markers in this case introduces various issues. The main one is that keeping the partial result of histedit as obsolete prevents us to recreates the same nodes in a second attempt. The same operation will lead to an identical results, using an identical node that already exists in the repository as obsolete. To conclude, we cannot and should not switch to obsolescence markers creation on histedit --abort and we backout 6f0b7475cf9a. A test to catch this class of issue will be introduced in the next changeset.

histedit: backout changeset 2b599f5468a4 Its parent is about to be backedout so this one needs to be removed too.