(FACT-2995) Fix order dependent test
(FACT-2995) Fix order dependent test

Before this commit, running rspec with random order could give
unexpected failures with certain seeds in os release tests. This was due
to the cached resolver being invalidated only after tests instead of
before also.

This commit adds the necessary cache invalidation and allows tests to
pass without dependency to order execution.

puppetlabs/facter,puppetlabs/facter,puppetlabs/facter