Fix regressions introduced in web-platform-tests#13893 (web-platform-…

…tests#13908)

Let sender sends some media data so that getStats produce some outbou…

…nd rtp related stats (web-platform-tests#13907)

Merge pull request web-platform-tests#13905 from youennf/move-onaddst…

…ream-to-legacy

Move onaddstream test to webrtc/legacy

Remove unneeded setting of onaddstream (web-platform-tests#13904)

Remove unneeded setting of onaddstream

Move RTCRtpTransceiver tests related to OfferToReceive legacy options…

… to webrtc/legacy (web-platform-tests#13903)

Merge pull request web-platform-tests#13901 from youennf/remove-furth…

…er-offerToReceiveXX

Use addTransceiver instead of offerToReceive options if possible

Merge pull request web-platform-tests#13899 from youennf/move-offerTo…

…ReceiveAudio-addTransceiver-audio

Move from offerToReceiveAudio to addTransceiver('audio')

Merge pull request web-platform-tests#13898 from youennf/fix-jsep-ini…

…tial-offer.https.html

Use generateVideoReceiveOnlyOffer instead of legacy offerToReceiveVideo

Merge pull request web-platform-tests#13897 from youennf/move-offerTo…

…Receive-tests-to-webrtc-legacy

Move some offerToReceive tests to webrtc/legacy

Merge pull request web-platform-tests#13896 from youennf/fix-getStats…

…-addTransceiver

Send media content to get inbound rtp stats