Suppress data races in sctp_close.

More visible in parallel execution of tsanv2, suppression needed for now
to launch parallel in main waterfall.

BUG=chromium:445880, webrtc:5151
R=kjellander@webrtc.org

Review URL: https://codereview.webrtc.org/1433433002 .

Cr-Commit-Position: refs/heads/master@{#10478}
diff --git a/webrtc/build/sanitizers/tsan_suppressions_webrtc.cc b/webrtc/build/sanitizers/tsan_suppressions_webrtc.cc
index b05bbb6..94a4387 100644
--- a/webrtc/build/sanitizers/tsan_suppressions_webrtc.cc
+++ b/webrtc/build/sanitizers/tsan_suppressions_webrtc.cc
@@ -68,6 +68,9 @@
 // TODO(jiayl): https://code.google.com/p/webrtc/issues/detail?id=3492
 "race:user_sctp_timer_iterate\n"
 
+// https://code.google.com/p/webrtc/issues/detail?id=5151
+"race:sctp_close\n"
+
 // Potential deadlocks detected after roll in r6516.
 // https://code.google.com/p/webrtc/issues/detail?id=3509
 "deadlock:webrtc::RTCPReceiver::SetSsrcs\n"