Implement clojure.core/shuffle

[jeaye]

This is similar to #178 but should use std::shuffle and return a persistent vector, rather than a sequence.

https://en.cppreference.com/w/cpp/algorithm/random_shuffle

Current source

(defn shuffle
  "Return a random permutation of coll"
  [#_java.util.Collection coll]
  ;; (let [al (java.util.ArrayList. coll)]
  ;;   (java.util.Collections/shuffle al)
  ;;   (clojure.lang.RT/vector (.toArray al)))
  (throw "TODO: port"))

[bpiel]

I'll take this