determinator paths fixtures

This fixture is used to test that path matching works correctly across platforms.

git-diff.out: The output of git diff -z --name-only f9ddae14671073f9fe847f8c6190de596f87a119^ f9ddae14671073f9fe847f8c6190de596f87a119, identical on Windows and Linux.
guppy-win.json: cargo metadata output on Windows.
guppy-linux.json: cargo metadata output on Linux.