(#8268) Fix resource harness spec tests

The windows file type requires that the path start with either a drive
letter or UNC style path. Also Ruby's File implementation on windows
only supports 0644 and 0444 permission bits (it doesn't differentiate
between group and other, and it doesn't know about the execute bit).
This commit maps the path and permissions used in the test to sensible
values when running on windows.

Paired-with: Jacob Helwig <jacob@puppetlabs.com>