ported AKS test for primes solution on rosettacode to Rust latest

I had 5 mins after lunch and I did a test of Rust archaeology (as per https://github.com/Hoverbear/rust-rosetta/issues/170). For these "algorithmic" sort of tasks the modernization looks easy enough, but maybe I got a particularly easy one...

`take` is not needed here.

Also `&ref` isn't needed, so you can leave the tuple as `(i, exp)`.