feature idea: option to automate bisecting a gist against nightly builds

Often something -- bug or fix, upstream or local -- will change in Electron and one part of my task is to figure out the commit where the change happened. I do this with Fiddle if I have a testcase, using Fiddle's bisect to manually bisecting through releases to narrow the change down to a specific day (or, if the nightlies were broken, a couple of days :roll_eyes:). This is much nicer than the alternatives, e.g. `git bisect` + `e sync` + `e build`, since the nightlies are already built and Fiddle fetches them so helpfully.

Manually bisecting in Fiddle doesn't take up _that_ much manual time, but it's a pattern that I've been repeating and probably will keep repeating, so I'm considering writing a patch to automate it.

I thought I'd open an issue first to get feedback, e.g. if anyone else would like this, or if there's already a better way to do it that I should be using instead :slightly_smiling_face:

_Edit:_ I was unclear, I know a bisect helper already exists -- what I'm thinking about is automating it e.g. having a testcase with an exit code to report success or failure so I could specify the bisect range and then Fiddle would do all the inbetween steps and then tell me where the state changed without me needing to manually run & evaluate the test each time.