.arcconfig

revlog: optimize ancestors() to not check filtered revisions for each

While reviewing the Rust implementation, I noticed iter(ancestors) doesn't
need to check filtering state for each parent revision. And doing that appears
to have some measurable perf win.

  $ hg perfancestors -R mercurial
  (orig) wall 0.038093 comb 0.040000 user 0.040000 sys 0.000000 (best of 100)
  (this) wall 0.024795 comb 0.020000 user 0.020000 sys 0.000000 (best of 117)

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}