ocaml: phase 5.1 shuffle.ml baseline (Fisher-Yates with deterministic Random)

In-place Fisher-Yates shuffle using:

  Random.init 42                  deterministic seed
  let a = Array.of_list xs
  for i = n - 1 downto 1 do       reverse iteration
    let j = Random.int (i + 1)
    let tmp = a.(i) in
    a.(i) <- a.(j);
    a.(j) <- tmp
  done

Sum is invariant under permutation, so the test value (55 for
[1..10] = 1+2+...+10) verifies the shuffle is a valid permutation
regardless of which permutation the seed yields.

Exercises Random.init / Random.int + Array.of_list / to_list /
length / arr.(i) / arr.(i) <- v + downto loop + multi-statement
sequencing within for-body.

33 baseline programs total.

lib/ocaml/baseline/expected.json

@@ -29,6 +29,7 @@
   "quicksort.ml": 44,
   "roman.ml": 44,
   "safe_div.ml": 20,
+  "shuffle.ml": 55,
   "sieve.ml": 15,
   "sum_squares.ml": 385,
   "unique_set.ml": 9,