Adding TSAN suppression for test posix udp transport.

This is race for reading a bool in the WebRTC test UDP transport and
not in any production code.

R=kjellander@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2159006

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4663 4adac7df-926f-26a2-2b94-8c16560cd09d

tools/valgrind-webrtc/tsan/suppressions.txt

@@ -31,6 +31,15 @@
   fun:webrtc::Trace::Add
   ...
 }
+{
+  Test posix socket HasIncoming
+  ThreadSanitizer:Race
+  fun:webrtc::test::UdpSocketPosix::HasIncoming
+  fun:webrtc::test::UdpSocketManagerPosixImpl::Process
+  fun:webrtc::test::UdpSocketManagerPosixImpl::Run
+  fun:webrtc::ThreadPosix::Run
+  fun:webrtc::StartThread
+}
 
 #-----------------------------------------------------------------------
 # 2. libjingle stuff (talk folder)