Add suppressions for two bugs found on TSan/UI...

tools/valgrind/tsan/suppressions.txt

Index: tools/valgrind/tsan/suppressions.txt
===================================================================
--- tools/valgrind/tsan/suppressions.txt	(revision 64401)
+++ tools/valgrind/tsan/suppressions.txt	(working copy)
@@ -55,6 +55,13 @@
   fun:ThreadSanitizerStartThread
 }
 
+{
+  bug_61210
+  ThreadSanitizer:Race
+  ...
+  fun:linked_ptr<PluginGroup>*
+}
+
 ############################
 # Real races in third_party
 {
@@ -253,6 +260,16 @@
 }
 
 ############################
+# Races in V8
+
+# http://code.google.com/p/v8/issues/detail?id=361
+{
+  Race on Locker::active_ in v8
+  ThreadSanitizer:Race
+  fun:v8::Locker::*
+}
+
+############################
 # Benign races in libc
 
 # A benign race inside the implementation of internal libc mutex