Assign negative stat bonuses for quiet moves at Pv nodes
This patch assigns negative stat bonuses for quiet moves
at pv nodes which are searched at depth greater than
this node assumes, so are extended.
Passed STC:
https://tests.stockfishchess.org/tests/view/6426198bdb43ab2ba6f9cfa2
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 548944 W: 147287 L: 146254 D: 255403
Ptnml(0-2): 1662, 59772, 150671, 60605, 1762
Passed LTC:
https://tests.stockfishchess.org/tests/view/642be4f177ff3301150d892d
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 93352 W: 25400 L: 24994 D: 42958
Ptnml(0-2): 44, 8817, 28547, 9225, 43
closes https://github.com/official-stockfish/Stockfish/pull/4495
bench 5044536