[javascript-stacking-context-001.html]
  [document.elementFromPoint() for point on region border, with all regions overlapping with non-auto z-index]
    expected: FAIL

  [document.elementFromPoint() for point on region border, with regions partially overlapping with non-auto z-index]
    expected: FAIL

  [document.elementFromPoint() for point inside region (effectively, content node), with regions partially overlapping with non-auto z-index]
    expected: FAIL