[small-payload.tentative.https.window.html]
  [fetchLater() accepts payload[size=20\] in a POST request body of String in same-origin iframe.]
    expected: FAIL

  [fetchLater() accepts payload[size=20\] in a POST request body of ArrayBuffer in same-origin iframe.]
    expected: FAIL

  [fetchLater() accepts payload[size=20\] in a POST request body of FormData in same-origin iframe.]
    expected: FAIL

  [fetchLater() accepts payload[size=20\] in a POST request body of URLSearchParams in same-origin iframe.]
    expected: FAIL

  [fetchLater() accepts payload[size=20\] in a POST request body of Blob in same-origin iframe.]
    expected: FAIL

  [fetchLater() accepts payload[size=20\] in a POST request body of File in same-origin iframe.]
    expected: FAIL
