Add atomics implementation for ThreadSanitizer v2...

Add atomics implementation for ThreadSanitizer v2 (https://sites.google.com/a/chromium.org/dev/developers/testing/threadsanitizer-tsan-v2)

BUG=128314

Review URL: https://chromiumcodereview.appspot.com/10965035
Patch from Alexander Potapenko <glider@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12953 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/atomicops.h

@@ -151,7 +151,9 @@ Atomic64 Release_Load(volatile const Atomic64* ptr);
 } }  // namespace v8::internal
 
 // Include our platform specific implementation.
-#if defined(_MSC_VER) && \
+#if defined(THREAD_SANITIZER)
+#include "atomicops_internals_tsan.h"
+#elif defined(_MSC_VER) && \
   (defined(V8_HOST_ARCH_IA32) || defined(V8_HOST_ARCH_X64))
 #include "atomicops_internals_x86_msvc.h"
 #elif defined(__APPLE__) && \