obsolete: drop usage of changectx in '_computecontentdivergentset' Changectx are expensive and not needed there. The use of `repo.set` denote old code that predate the introduction of `repo.revs` that we now use. On my mercurial repository 495 draft: before: 0.054239 second after: 0.046935 second On a mercurial repository with 115973 draft: before: 0.564548 second after: 0.130534 second