tests: add test demonstrating regression in path audit
D785 regressed behavior in path auditing: files can be deleted if they have a
path that conflicts with a filename from a malicious remote or bundle.
This test demonstrates the problem - the file should not have been deleted.
Differential Revision: https://phab.mercurial-scm.org/D1156
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}