RembWithSendSideBwe: Rename |event_| to |stop_event_| and set it when the test ends.
RembWithSendSideBwe: Rename |event_| to |stop_event_| and set it when the test ends.

BUG=webrtc:7200
R=stefan@webrtc.org

Review-Url: https://codereview.webrtc.org/2706223002 .
Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#16744}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5dd5f5a3195c3a5fd26b6008992bb18af73d42d2

Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk