ocaml: phase 5.1 harshad.ml baseline (count Niven/Harshad numbers <= 100 = 33)

A Harshad (or Niven) number is divisible by its digit sum:

  let count_harshad limit =
    let c = ref 0 in
    for n = 1 to limit do
      if n mod (digit_sum n) = 0 then c := !c + 1
    done;
    !c

  count_harshad 100 = 33

All single-digit numbers (1..9) qualify trivially. Plus 10, 12, 18,
20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 70, 72, 80,
81, 84, 90, 100 (24 more) = 33 total under 100.

133 baseline programs total.

lib/ocaml/baseline/expected.json

@@ -59,6 +59,7 @@
   "grid_paths.ml": 210,
   "group_consec.ml": 53,
   "hailstone.ml": 111,
+  "harshad.ml": 33,
   "hamming.ml": 4,
   "hanoi.ml": 1023,
   "hist.ml": 75,