tests: use an absolute path to get around '..' being invalid on a dead CWD
Only FreeBSD seems to be this picky. Note that this explicit
absolute-path `cd` exposes a defect in the test, in that we end up
still inside the cwd-vanish repository, but that's not a regression in
this change. Since we're in a code freeze, I'm doing the smallest
thing possible to try and fix bugs on FreeBSD, rather than cleaning up
the entire problem. I'll follow up with a more complete fix after the
freeze.
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true