Check clock more often

Check clock more often

This patch changes the frequency with which the time is checked, changing
frequency from every 1024 counted nodes to every 512 counted nodes. The
master value was tuned for the old classical eval, the patch takes the
roughly 2x slowdown in nps with SFNNUEv7 into account. This could reduce
a bit the losses on time on fishtest, but they are probably unrelated.

passed STC:
https://tests.stockfishchess.org/tests/view/64bb8ae5dc56e1650abb1b11
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 76576 W: 19677 L: 19501 D: 37398
Ptnml(0-2): 274, 8592, 20396, 8736, 290

closes https://github.com/official-stockfish/Stockfish/pull/4704

No functional change