Add a reduced test case for issue 4379

This should have been part of PR #5136.

Based on comments https://github.com/mozilla/pdf.js/issues/4379#issuecomment-51221787 and https://github.com/mozilla/pdf.js/issues/4379#issuecomment-51475463, it should be OK to include the PDF file in the repo.

**Edit:** Even though there are other files in the test suite which PR #5136 fixed, having a small self-contained test case just for the actual issue is much simpler when trying to fix regressions.