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/LibWeb/Bindings/XMLHttpRequestConstructor.cpp

@@ -35,6 +35,7 @@ namespace Web {
 namespace Bindings {
 
 XMLHttpRequestConstructor::XMLHttpRequestConstructor()
+    : NativeFunction(*interpreter().function_prototype())
 {
     put("length", JS::Value(1));
 }