(#8272) Refactor specs for Windows service provider

These were using fake objects when that's not really necessary, so replace them
with real ones. Additionally, many of these specs were doing the same thing
(like creating a resource), so that has been extracted to the before block.

Reviewed-By: Jacob Helwig <jacob@puppetlabs.com>
(cherry picked from commit f5e8dbef9e16bf05e4c05a43407e94027faa2410)