Support skipping a version in bisect

[nornagon]

Similarly to git bisect skip. Sometimes, a given version is not a good one to test, e.g. because it crashes on launch (looking at you, v8.0.0-nightly.20191021). I'd like to be able to test a nearby version instead, since I don't know whether to mark this particular version as good or bad.

[Hanaffi]

@codebytere I already submitted PR for the assigned issue. Can you assign me this?

[erickzhao]

@Hanaffi I don't see a PR from you in the queue. 🤔

[Hanaffi]

@erickzhao Its there: #1092 :)

[Hanaffi]

@codebytere @erickzhao Can you give some hints on this one? IDK where to start

[chan95821]

Hello. As git bisect uses the same searching procedure for both bad and skipping situations, is it a right approach to just add a skip button in the renderer?

[erickzhao]

Hey @chan95821, I think the git code actually uses a pseudo-random number generator to determine the next commit to test:

https://github.com/git/git/blob/a36e024e989f4d35f35987a60e3af8022cac3420/bisect.c#L620-L651