Suppress races in event tracing code.
Suppress races in event tracing code.

Due to lack of atomics our tracing code is broken and triggering real
errors in ThreadSanitizer.

R=kjellander@webrtc.org
BUG=2497
TEST=out-tsan/out/Debug/libjingle_media_unittest --gtest_filter=WebRtcVideoMediaChannelTest.GetStatsMultipleRecvStreams + verifying that "race:*trace_event_unique_catstatic*" exists in the list of matched suppressions.

Review URL: https://webrtc-codereview.appspot.com/35719004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@8022 4adac7df-926f-26a2-2b94-8c16560cd09d

jchavanton/webrtc,krieger-od/nwjs_chromium_webrtc,Alkalyne/webrtctrunk,krieger-od/nwjs_chromium_webrtc,sippet/webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,aleonliao/webrtc-trunk,PersonifyInc/chromium_webrtc,Alkalyne/webrtctrunk,aleonliao/webrtc-trunk,krieger-od/nwjs_chromium_webrtc,PersonifyInc/chromium_webrtc,PersonifyInc/chromium_webrtc,aleonliao/webrtc-trunk,krieger-od/nwjs_chromium_webrtc,PersonifyInc/chromium_webrtc,sippet/webrtc,sippet/webrtc,Alkalyne/webrtctrunk,krieger-od/nwjs_chromium_webrtc,jchavanton/webrtc,PersonifyInc/chromium_webrtc,jchavanton/webrtc,jchavanton/webrtc,krieger-od/webrtc,sippet/webrtc,krieger-od/webrtc,jchavanton/webrtc,PersonifyInc/chromium_webrtc,krieger-od/webrtc,Alkalyne/webrtctrunk,krieger-od/nwjs_chromium_webrtc,sippet/webrtc,krieger-od/webrtc,Alkalyne/webrtctrunk,krieger-od/webrtc,aleonliao/webrtc-trunk,sippet/webrtc,jchavanton/webrtc,krieger-od/webrtc,aleonliao/webrtc-trunk,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk