inhibit: use dirty revset trick to speedup the inhibit search space. See documentation for details. I'm a bit sad about this changesets.

inhibit: use 'repo.revs' instead of 'repo.set' This skip the creation of a changectx object.

_inhibitmarkers: turn the result from generator into a list A generator object is always True, we have to turn it into a list in order to be able to use it in the tests. Before this patch we were rewriting the 'obsinhibit' file all the time, this had a performance impact especially on repository where transaction are expensive (hooks, cache invalidation, etc). Writing this file less often have a minor effect on test where a stripped changeset does not get removed from the obsinhibit file is still inhibited when unbundled back. I think this is fine and I'm moving forward.

split: drop the experimental flag I've been using it without issue for some time. The only blocker in my mind was the lack of commit message preservation and this is now fixed.