LibJS+LibWeb: Pass prototype to Object constructor

Everyone who constructs an Object must now pass a prototype object when
applicable. There's still a fair amount of code that passes something
fetched from the Interpreter, but this brings us closer to being able
to detach prototypes from Interpreter eventually.

Libraries/LibJS/Runtime/Error.cpp

@@ -37,7 +37,8 @@ Error* Error::create(GlobalObject& global_object, const FlyString& name, const S
 }
 
 Error::Error(const FlyString& name, const String& message, Object& prototype)
-    : m_name(name)
+    : Object(&prototype)
+    , m_name(name)
     , m_message(message)
 {
     set_prototype(&prototype);