Simplify statScore divisor into a constant
Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/665b392ff4a1fd0c208ea864
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 114752 W: 29628 L: 29495 D: 55629
Ptnml(0-2): 293, 13694, 29269, 13827, 293
Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/665b588c11645bd3d3fac467
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 65322 W: 16549 L: 16373 D: 32400
Ptnml(0-2): 30, 7146, 18133, 7322, 30
closes https://github.com/official-stockfish/Stockfish/pull/5337
bench 1241443