ocaml: phase 5.1 partition_count.ml baseline (p(15) = 176)

Counts integer partitions via classic DP:

  let partition_count n =
    let dp = Array.make (n + 1) 0 in
    dp.(0) <- 1;
    for k = 1 to n do
      for i = k to n do
        dp.(i) <- dp.(i) + dp.(i - k)
      done
    done;
    dp.(n)

  partition_count 15 = 176

Tests Array.make, .(i)<-/.(i) array access, nested for-loops, refs.

135 baseline programs total.

lib/ocaml/baseline/expected.json

@@ -95,6 +95,7 @@
   "palindrome_sum.ml": 49500,
   "paren_depth.ml": 7,
   "partition.ml": 3025,
+  "partition_count.ml": 176,
   "pancake_sort.ml": 910,
   "pascal.ml": 252,
   "peano.ml": 30,