LibJS: Clarify Object (base class) construction somewhat

Divide the Object constructor into three variants:

- The regular one (takes an Object& prototype)
- One for use by GlobalObject
- One for use by objects without a prototype (e.g ObjectPrototype)

Libraries/LibJS/Runtime/Error.cpp

@@ -37,7 +37,7 @@ Error* Error::create(GlobalObject& global_object, const FlyString& name, const S
 }
 
 Error::Error(const FlyString& name, const String& message, Object& prototype)
-    : Object(&prototype)
+    : Object(prototype)
     , m_name(name)
     , m_message(message)
 {