[event-constructor.html]
  [can't bypass required members by omitting the dictionary entirely]
    expected: FAIL

  [destination is required]
    expected: FAIL

  [signal is required]
    expected: FAIL

  [all properties are reflected back]
    expected: FAIL

  [defaults are as expected]
    expected: FAIL

  [hasUAVisualTransition is default false]
    expected: FAIL