Given the non-standard nature of IQ testing, there's no way they would accept a result that you acquired elsewhere, especially not an internet-based test like the ones on high-IQ sites. More likely is that they would administer a test themselves with their own specialist psychologist to determine whether you have the type of intelligence/skills necessary to perform the duties they need.
Oh wait, isn't that exactly the same as a job interview?
Oh wait, isn't that exactly the same as a job interview?