Simplify away piece count condition for useClassical
Simplify away the piece count condition for useClassical. In compensation, the psq requirement is increased by 15%.
Also updated the Elo estimate for useClassical, based on recent testing.
Simplification STC:
https://tests.stockfishchess.org/tests/view/642acbb577ff3301150d3ef5
LLR: 2.96 (-2.94,2.94) <-1.75,0.25>
Total: 51984 W: 13906 L: 13707 D: 24371
Ptnml(0-2): 150, 5638, 14227, 5817, 160
Simplification LTC:
https://tests.stockfishchess.org/tests/view/642b9c5777ff3301150d778a
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 119696 W: 32412 L: 32300 D: 54984
Ptnml(0-2): 53, 11529, 36567, 11651, 48
closes https://github.com/official-stockfish/Stockfish/pull/4494
Bench: 5089321