repair: improve performance of detection of revisions affected by
issue6528
Explanations inside the patch. I've tested this on Mozilla-Central and it's
5 times faster than the naive approach on my laptop.
Differential Revision: https://phab.mercurial-scm.org/D11262
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}