(#17811) Add test for group name to gid conversion

On OS X, the primary group for a user must be specified as a numeric id and not
a string. There was code to ensure this happens, but it was guarded by a faulty
logic statement and there was no test to catch the bug.
(#17811) Ensure PrimaryGroupID is converted to Int

On OS X, the PrimaryGroupID for a user must be an integer. Ensure this happens
by running `:gid` attributes through `Puppet::Util.gid`.
(#20284) Output one item per line for arrays in console output

To make it easier to read, pipe output and make shell loop from output
from faces it is good if they are printed one item per line for arrays.
Merge pull request #1606 from dalen/array_render_as_s

(#20284) Output one item per line for arrays in console output
Merge pull request #1600 from Sharpie/17811-os-x-fix-gid-conversion

(#17811) Fix group id conversion for OS X users