Tweak quiet move bonus

Tweak quiet move bonus

Improving quiet move bonus by replacing bestvalue and alpha comparison, with
checking the statScore of the previous search step instead.

Inspired by @locutus2

Passed STC:
https://tests.stockfishchess.org/tests/view/657f22fb893104ee25b614e8
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 51296 W: 13121 L: 12774 D: 25401
Ptnml(0-2): 225, 5986, 12868, 6355, 214

Passed LTC:
https://tests.stockfishchess.org/tests/view/658024a2893104ee25b62587
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 82758 W: 20606 L: 20189 D: 41963
Ptnml(0-2): 51, 9149, 22555, 9580, 44

closes https://github.com/official-stockfish/Stockfish/pull/4930

Bench: 1312822