Tweak statscore for captures
Followup of a recent patch that separated statscore for captures and non-captures.
Lower value that we subtract from statscore if a move is a capture.
Passed STC:
https://tests.stockfishchess.org/tests/view/67385b6786d5ee47d953eeba
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 50592 W: 13223 L: 12888 D: 24481
Ptnml(0-2): 154, 5853, 12931, 6220, 138
Passed LTC:
https://tests.stockfishchess.org/tests/view/6739056e86d5ee47d953ef3f
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 23598 W: 6155 L: 5862 D: 11581
Ptnml(0-2): 16, 2466, 6543, 2757, 17
closes https://github.com/official-stockfish/Stockfish/pull/5682
Bench: 771180