Refine stat based reductions
This patch separates stat based reductions for quiet moves in case of being in check and in case of not being in check.
We will be using sum of first continuation history and main history (similar to movepicker) instead of statScore for the first case.
passed STC
https://tests.stockfishchess.org/tests/view/5ff87b2f6019e097de3ef09b
LLR: 2.93 (-2.94,2.94) {-0.25,1.25}
Total: 63992 W: 5887 L: 5678 D: 52427
Ptnml(0-2): 201, 4561, 22305, 4686, 243
passed LTC
https://tests.stockfishchess.org/tests/view/5ff8b6206019e097de3ef0b2
LLR: 2.94 (-2.94,2.94) {0.25,1.25}
Total: 81216 W: 3127 L: 2880 D: 75209
Ptnml(0-2): 46, 2544, 35176, 2801, 41
closes https://github.com/official-stockfish/Stockfish/pull/3293
bench 4395984