LibWeb: Move setting of Web object prototypes to initialize()

This needs to happen before prototype/constructor intitialization can be
made lazy. Otherwise, GC could run during the C++ constructor and try to
collect the object currently being created.

Userland/Libraries/LibWeb/DOM/Range.h

@@ -88,6 +88,8 @@ private:
     explicit Range(Document&);
     Range(Node& start_container, u32 start_offset, Node& end_container, u32 end_offset);
 
+    virtual void initialize(JS::Realm&) override;
+
     Node& root();
     Node const& root() const;