Fix broken unit tests

The test cases in `tests.run_various_tests_on_various_files.GlyphsRT` seem to have bit-rotted; quite many of these tests are failing on the current master branch. Should they be removed, since nobody appears to run them? Otherwise, could they get fixed and then run by default, or at least on Travis?

Start with tests.run_various_tests_on_various_files.GlyphsRT and run the current test suite to identify which cases fail on master. Review the existing test configuration and Travis setup; done means the tests are either repaired and run by default or on Travis, or their removal is explicitly resolved.

Written by the indexing model from the issue text.