Remove usage of RtpRtcp::SetSSRC() in RtpRtcpImplTest
Remove usage of RtpRtcp::SetSSRC() in RtpRtcpImplTest

Bug: webrtc:10774
Change-Id: Ifaf82776d547ed1c2ca99c27c1deda4060d18ec2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/152164
Commit-Queue: Erik Språng <3ab8c90c99d6dd7822e0fad803ab0211dd287ae5@webrtc.org>
Reviewed-by: Danil Chapovalov <55de8d9c2b5977da2dd48f967f21f9d606b172a5@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29115}

TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc