Move David Bruant's DOM Events tests into position.
Remove an unnecessary element.
Use window.onerror instead of window.addEventListener('error').

I believe the spec actually supports the latter now, but that is not the main goal of this test.
Use assert_equals for better error messages.
Remove an unnecessary element.
Remove unnecessary references to TestTWF.
Make throwing-in-listener-and-window-error-event.html actually work.
Remove an unnecessary element from event-phases-order.html.
Merge pull request #58 from w3c/submission/DavidBruant/DOMEvents

Move @DavidBruant's DOM Events tests into position.