A follow-up to MAGNOLIA-8639.

ExclusionsFilterTest#excludedDirectoryAreExcludedEveryWhereNotJustInRootWindowsSeparator was using some reflection magic to simulate a Windows-like file separator. However, this is no longer allowed in Java 17.
The test has been rewritten and uses a Junit5's annotation to run on Windows only.
Problem with this approach is that with our current CI setup it will basically be always ignored.

Here are some proposals:

• Can we just remove the test, is it actually of value to us?
• Can we rewrite it in a better way?
  • Looking at info.magnolia.resourceloader.file.ExclusionsFilter#test and org.apache.commons.io.FilenameUtils#normalize(..) , it seems that the test is borked anyway: File.separator is not used at all by that implementation
• Could we set up a Jenkins build pipeline to run the test on Windows?
  • Is it worth for just one test though?