(#23249) Normalize tidy paths

[joshcooper]

Previously, a tidy resource could create a duplicate file resource due to a
mismatch between back and forward slashes on Windows.

This commit munges the tidy path parameter using File.expand_path, so on
Windows, C:\dir becomes C:/dir. When that is File.join'ed with a file
needing to be tidy'ed, the resulting path contains only forward slashes,
which is consistent with the path parameter for the file type.

[ferventcoder]

@joshcooper any thoughts why the below is happening?

 expected: "c:/directory"
 got: "/home/travis/build/puppetlabs/puppet/c:\\directory"

[ferventcoder]

@joshcooper Wasn't there also an issue with case as well? So c:/bob is different than c:/Bob?

I'm not sure how to address this exactly though as I believe the user would want the directory/file created in exactly the case that they specify.

Perhaps we can do some more normalization of the resource title to all lowercase and add set the path in the case that the user specifies?

[puppetcla]

CLA signed by all contributors.

[joshcooper]

When running on non-windows, the as_platform block redefines File::SEPARATOR and File::ALT_SEPARATOR to be as expected, '/' and '\' on windows. I assumed that File.expand_path would use those constants, but it doesn't since it calls into native code, where those constants are not redefined by the as_platform block. I will need to redo this PR.