This fixes a few issues I encountered recently when working with Testbed:

• TESTBED: Small Improvements & Bugfixes #6605 did not correctly handle the new setting to set non-interactive mode. It's not clear how I missed that (probably during cherry-picking for the PR). I also changed the behaviour to always run all (non-interactive) tests in non-interactive mode, as there's no way to select the tests when launching it non-interactive.
• Trac#15754 turned out to be an issue with the test. It's not clear if this ever worked as the handling of trailing dots is in SearchMan, not FSDirectory. I checked the AGOS engine and it also uses SearchMan, so this should now be correct. Maybe this test pre-dates SearchMan?
• The ImageAlbum test also didn't work. Also a bug in the test itself which should now be fixed (the images are in a subfolder that wasn't added to SearchMan).
• There was a correctly failing test in the save game tests, I fixed the issue by properly setting the errors.