[RTCDTMFSender-ontonechange-long.https.html]
  [insertDTMF with duration greater than 6000 should be clamped to 6000]
    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1402717
    expected:
      if (os == "win") and not debug and (processor == "x86_64"): [PASS, FAIL]