merge: add a config option to disable path conflict checking
We've found a severe perf regression in `hg update` caused by the path conflict
checking code. The next patch will disable this by default.
Differential Revision: https://phab.mercurial-scm.org/D1222
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}