Simplify Probcut Condition
Rebased and properly guarded #5720
Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 179616 W: 45764 L: 45706 D: 88146
Ptnml(0-2): 125, 19665, 50162, 19739, 117
https://tests.stockfishchess.org/tests/view/677590531a2f267f20548b82
Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 445728 W: 113467 L: 113682 D: 218579
Ptnml(0-2): 331, 49226, 123900, 49141, 266
https://tests.stockfishchess.org/tests/view/67734f351a2f267f205489d9
closes https://github.com/official-stockfish/Stockfish/pull/5758
Bench: 1180421