Simplify the highBestMoveEffort formula in Time management
Passed STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 22272 W: 5885 L: 5655 D: 10732
Ptnml(0-2): 76, 2329, 6108, 2535, 88
https://tests.stockfishchess.org/tests/view/69244d07ba083df4ca63e02b
Passed LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 48690 W: 12405 L: 12221 D: 24064
Ptnml(0-2): 29, 4755, 14597, 4931, 33
https://tests.stockfishchess.org/tests/view/6924de9aba083df4ca63e327
closes https://github.com/official-stockfish/Stockfish/pull/6451
No functional change