Oilpan: Avoid declaring a destructor for garbage collected ListHashSet.

Source/wtf/LinkedHashSet.h

Index: Source/wtf/LinkedHashSet.h
diff --git a/Source/wtf/LinkedHashSet.h b/Source/wtf/LinkedHashSet.h
index 9b8fb79c16f4957f7170cf827143e2039e900b93..eb235d4ee7de6cfe8608ece4834bc1e339b0c443 100644
--- a/Source/wtf/LinkedHashSet.h
+++ b/Source/wtf/LinkedHashSet.h
@@ -177,6 +177,8 @@ public:
     LinkedHashSet();
     LinkedHashSet(const LinkedHashSet&);
     LinkedHashSet& operator=(const LinkedHashSet&);
+
+    // Needs finalization. The anchor needs to unlink itself from the chain.
     ~LinkedHashSet();
 
     static void finalize(void* pointer) { reinterpret_cast<LinkedHashSet*>(pointer)->~LinkedHashSet(); }