Do not fire timers for finalizing objects.

Source/platform/heap/Heap.h

Index: Source/platform/heap/Heap.h
diff --git a/Source/platform/heap/Heap.h b/Source/platform/heap/Heap.h
index 52ecf0673835cac59fe74693cd537382b00f4b97..0314c8be45b428a2f0791eeb34ff15643295e3ba 100644
--- a/Source/platform/heap/Heap.h
+++ b/Source/platform/heap/Heap.h
@@ -818,6 +818,11 @@ public:
     static bool containedInHeapOrOrphanedPage(void*);
 #endif
 
+    // Is the traceable GC object still alive? If no GC is in progress,
+    // it will be true. If a GC (lazy sweep, really) is in progress,
+    // it will be true iff the object has been marked.
+    static bool isObjectAlive(const void*);
+
     // Push a trace callback on the marking stack.
     static void pushTraceCallback(void* containerObject, TraceCallback);