Revert "Merge pull request #358 from ayg/submission/ayg-use-webidl2"

This reverts commit d4dbf977ec2460eda4af57434b795069aaf62948, reversing
changes made to d2a10f31b00df85aa0a4f8b242785d838f82f788.

Provided [notes in the original PR](https://github.com/w3c/web-platform-tests/pull/358#issuecomment-25702446) on how to recover from this merge and proceed with the pull request.