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/MathObject.cpp

@@ -33,6 +33,7 @@
 namespace JS {
 
 MathObject::MathObject()
+    : Object(interpreter().object_prototype())
 {
     put_native_function("abs", abs, 1);
     put_native_function("random", random);