Change ttmove reduction logic, and values
Passed STC:
LLR: 2.93 (-2.94,2.94) <0.00,2.00>
Total: 38112 W: 10024 L: 9708 D: 18380
Ptnml(0-2): 104, 4365, 9830, 4625, 132
https://tests.stockfishchess.org/tests/view/69dd25a33ca80bdf151d4b33
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 256926 W: 65744 L: 64977 D: 126205
Ptnml(0-2): 126, 27919, 71612, 28674, 132
https://tests.stockfishchess.org/tests/view/69de48645c67bee7d241ff4e
Passed VLTC non-reg:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 174386 W: 44640 L: 44578 D: 85168
Ptnml(0-2): 26, 17847, 51384, 17911, 25
https://tests.stockfishchess.org/tests/view/69e767370e9667dd5a76551b
closes https://github.com/official-stockfish/Stockfish/pull/6782
Bench: 2788824