Remove reduced LMR capture bonus
In LMR, simplify away the reduced capture bonus (i.e. if (capture) bonus /= 6).
Non-regression STC: https://tests.stockfishchess.org/tests/view/63da1da9bbadd17b3787dced
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 28152 W: 7521 L: 7296 D: 13335
Ptnml(0-2): 76, 3069, 7568, 3280, 83
Non-regression LTC: https://tests.stockfishchess.org/tests/view/63da6ad4bbadd17b3787e98c
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 52472 W: 14120 L: 13941 D: 24411
Ptnml(0-2): 16, 5071, 15887, 5242, 20
closes https://github.com/official-stockfish/Stockfish/pull/4378
Bench: 4034016