Added two suppressions for benign races in ICU

tools/valgrind/tsan/suppressions.txt

 ############################
 # Chromium
 
 {
   bug_15147
   ThreadSanitizer:Race
   ...
   fun:*URLRequestJobTracker*
 }
 
@@ skipping 69 matching lines @@
   fun:*WatchdogTest_*arm*Test_Test*TestBody*
 }
 
 # TODO(timurrrr): bug item
 {
   Data race on vfptr in base/thread_unittest
   ThreadSanitizer:Race
   ...
   fun:*ThreadTest_SleepInsideInit*TestBody*
 }
+
+############################
+# Benign races in ICU
+{
+  Two writes, same value (ICU gGlobalMutex, gMutexesInUse)
+  ThreadSanitizer:Race
+  fun:umtx_init_4_2
+}
+
+{
+  Two writes, same value (ICU gHeapInUse)
+  ThreadSanitizer:Race
+  fun:uprv_malloc_4_2
+}