[active.window.html]
  [document.open() removes the document's children (non-active document without an associated Window object; createHTMLDocument)]
    expected: FAIL

  [document.open() removes the document's children (non-active document without an associated Window object; XMLHttpRequest)]
    expected: FAIL

  [document.open() removes the document's children (non-active document without an associated Window object; DOMParser)]
    expected: FAIL

  [document.open() removes the document's children (non-active document with an associated Window object; navigated away)]
    expected: FAIL