Remove nmpColor

Remove nmpColor

no benefit seen, neither in game play nor for zugzwang test positions

STC: https://tests.stockfishchess.org/tests/view/642e293977ff3301150e9b55
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 161848 W: 43332 L: 43254 D: 75262
Ptnml(0-2): 418, 16987, 46058, 17021, 440

LTC: https://tests.stockfishchess.org/tests/view/642fea9420eb941419bde296
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 120208 W: 32529 L: 32418 D: 55261
Ptnml(0-2): 35, 11424, 37080, 11525, 40

closes https://github.com/official-stockfish/Stockfish/pull/4511

bench 3979409