Cheaper thread-safe atomic initialization of static references.

Source/platform/heap/Visitor.cpp

Index: Source/platform/heap/Visitor.cpp
diff --git a/Source/platform/heap/Visitor.cpp b/Source/platform/heap/Visitor.cpp
index 4256c1c3366c22442f4f0181b0df8b86914bcd6c..d5bc469abf586172842bb25d4df8397856021689 100644
--- a/Source/platform/heap/Visitor.cpp
+++ b/Source/platform/heap/Visitor.cpp
@@ -48,7 +48,7 @@ void GCInfoTable::ensureGCInfoIndex(const GCInfo* gcInfo, size_t* gcInfoIndexSlo
     ASSERT(gcInfo);
     ASSERT(gcInfoIndexSlot);
     // Keep a global GCInfoTable lock while allocating a new slot.
-    AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);
+    AtomicallyInitializedStaticReference(Mutex, mutex, new Mutex);
     MutexLocker locker(mutex);
 
     // If more than one thread ends up allocating a slot for