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
{header}
<title>Error</title>
<description>Error</description>
<item>
<title>Error</title>
<description>{error|escape}</description>
<guid>https://mercurial-scm.org/#error</guid>
</item>
</channel>
</rss>