🔍 NMP, tweak reduction using eval - beta

[eduherminio]

+ Math.Min(NMP_StaticEvalBetaMaxReduction, staticEvalBetaDiff / NMP_StaticEvalBetaDivisor).

Continuation of efforts in https://github.com/lynx-chess/Lynx/pull/837/files

Test  | nmp/tweak-reduction-staticeval-2
Elo   | -0.90 +- 2.56 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -2.26 (-2.25, 2.89) [0.00, 3.00]
Games | 32014: +8832 -8915 =14267
Penta | [874, 3877, 6526, 3918, 812]
https://openbench.lynx-chess.com/test/886/

Test  | nmp/tweak-reduction-staticeval-2
Elo   | 0.50 +- 1.32 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | -2.25 (-2.25, 2.89) [0.00, 3.00]
Games | 120212: +33182 -33009 =54021
Penta | [3121, 14545, 24530, 14860, 3050]
https://openbench.lynx-chess.com/test/894/

Test  | nmp/tweak-reduction-staticeval-2
Elo   | 3.81 +- 2.65 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=128MB
LLR   | 2.92 (-2.25, 2.89) [0.00, 3.00]
Games | 24974: +6443 -6169 =12362
Penta | [424, 2898, 5552, 3206, 407]
https://openbench.lynx-chess.com/test/914/