Tests that dispatchEvent's argument is required to be an Event.
On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
PASS document.dispatchEvent(null) threw exception TypeError: Failed to execute 'dispatchEvent' on 'EventTarget': parameter 1 is not of type 'Event'..
PASS document.dispatchEvent(document) threw exception TypeError: Failed to execute 'dispatchEvent' on 'EventTarget': parameter 1 is not of type 'Event'..
PASS successfullyParsed is true
TEST COMPLETE