TSAN bot failure in MessagePumpLibevent::Run

Adds TSAN suppression for MessagePumpLibevent::Run.

BUG=104769
TEST=TSAN bots go green
TBR=thestig@chromium.org

Review URL: http://codereview.chromium.org/8588062

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110730 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/tsan/suppressions.txt

@@ -682,3 +682,13 @@
   ThreadSanitizer:Race
   fun:WebRTCAudioDeviceTest::SetUp
 }
+{
+   bug_104769
+   ThreadSanitizer:Race
+   fun:timeout_correct
+   fun:event_base_loop
+   fun:base::MessagePumpLibevent::Run
+   fun:MessageLoop::RunInternal
+   fun:MessageLoop::RunHandler
+   fun:MessageLoop::Run
+}