Small simplification in probCut movepicker
Remove no longer required condition for tt moves. The idea is that if tt the value is
greater than probCut beta try tt move that is a capture anyway - even if it
doesn't pass SEE check. This idea in various implementations passed some STCs
and was looking decent at LTCs as a gainer.
Passed STC:
https://tests.stockfishchess.org/tests/view/68aa1ee075da51a345a5a805
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 136160 W: 35189 L: 35079 D: 65892
Ptnml(0-2): 436, 16083, 34891, 16275, 395
Passed LTC:
https://tests.stockfishchess.org/tests/view/68aa91d375da51a345a5a884
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 80022 W: 20652 L: 20492 D: 38878
Ptnml(0-2): 33, 8717, 22357, 8865, 39
closes https://github.com/official-stockfish/Stockfish/pull/6259
Bench: 2307940