[select-parsing.tentative.html]
  [<button>s and <datalist>s should be allowed in <select>.]
    expected: FAIL

  [</select> should close <button>.]
    expected: FAIL

  [</select> should close <datalist>.]
    expected: FAIL

  [<select> in <button> in <select> should remove inner <select>.]
    expected: FAIL

  [<select> in <select><button><div> should remove inner <select>.]
    expected: FAIL

  [Nested <button>s or <datalist>s in <select> should be dropped.]
    expected: FAIL