Issue #1742 - Part 4: Don't trigger read barriers when comparing wrapped pointers types

This is actually an undocumented dependency of Bug 1325406 for Linux and
SunOS.

Ref: BZ 1308236

js/ipc/JavaScriptShared.cpp

@@ -100,7 +100,7 @@ IdToObjectMap::has(const ObjectId& id, const JSObject* obj) const
     auto p = table_.lookup(id);
     if (!p)
         return false;
-    return p->value().unbarrieredGet() == obj;
+    return p->value() == obj;
 }
 #endif