bisect: use standard one-line commit summary
This makes bisect use the standardized support for one-line commit
summary I added a while back. That means that it will respect the
`command-templates.oneline-summary` config. If also means that the
default output now includes the first line of the commit message (see
test impact).
Differential Revision: https://phab.mercurial-scm.org/D10245
{
"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"
}