Remove loopback setup in RtpRtcpImplTest. Changed to use two separate rtp/rtcp modules.
Remove loopback setup in RtpRtcpImplTest. Changed to use two separate rtp/rtcp modules.

R=mflodman@webrtc.org, pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/7259004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 871d949299a4ec27efe9805ad5c2289e7e2f68b3

sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc