Before this CL, the RTP state would be re-randomized after a recreation of VideoSendStream. That might lead to us sending a non-compliant RTP stream, which is avoided after the changes in this CL. BUG=webrtc:5654 TBR=pbos@webrtc.org # Trivial change to fuzzer. Review-Url: https://codereview.webrtc.org/2912713002 Cr-Commit-Position: refs/heads/master@{#18322}