nodemap: warm the persistent nodemap on disk with debugupdatecache
When appropriate, the nodemap cache file will be created.
Differential Revision: https://phab.mercurial-scm.org/D8173
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}