contrib/asv.conf.json

branchmap: do not specify changelog as an argument

Since (unfiltered)repo.changelog lookup gets as fast as __dict__ lookup,
there's no point to pass in changelog instance.

  $ hg perfbranchmap --clear-revbranch -R mozilla-central
  ! base
  (orig) wall 20.593091 comb 20.600000 user 20.520000 sys 0.080000 (best of 3)
  (this) wall 20.129126 comb 20.130000 user 20.020000 sys 0.110000 (best of 3)

This backs out most of the changes in 76d4272bd57b and 47c03042cd1d.

{
    "version": 1,
    "project": "mercurial",
    "project_url": "https://mercurial-scm.org/",
    "repo": "..",
    "branches": ["default", "stable"],
    "environment_type": "virtualenv",
    "show_commit_url": "https://www.mercurial-scm.org/repo/hg/rev/",
    "benchmark_dir": "benchmarks",
    "env_dir": "../.asv/env",
    "results_dir": "../.asv/results",
    "html_dir": "../.asv/html"
}