(PUP-3012) Accept. tests - 3.7 PMT updates upgrade

from John:
This commit adds additional acceptance test coverage for updates
to the puppet module upgrade command. These tests validate the
following:

* detection of symlinks in installed module
* detection of latest version already installed
* allow upgrade when invalid semver in installed modules

from Eric:
fixup John's PR for changes to upstream
pending_test more gracefully while waiting on fixes
pending tests on solaris until the forge cert issue is sorted
fix the symlink test so it works more uniformly on windows with cygwin
weirdness
  prior to this change, tar would fail on windows across the C:\
  boundary? we also ensure the moduledir exists (not always true on git
  installs)