Disable CallReportsRttForSender on Mac.
Disable CallReportsRttForSender on Mac.

BUG=webrtc:5938
TBR=pbos@webrtc.org
NOTRY=True

Review-Url: https://codereview.webrtc.org/2016933002
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12938}

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