 received not intersecting event, except
  // target4, which was already not intersecting due to being hidden.
  function runStep3() {
    const step = arguments.callee.name;
    t.step(() => {
      assert_equals(entries.length, 3, step);
      for (let i = 0; i < entries.length; ++i) {
        assert_false(entries[i].isIntersecting, step);
        assert_not_equals(entries[i].target, target4, step);
      }
    });

    entries = [];
    enqueueStep4();
  }

  // Scroll the elements back on screen.
  func