Increase base time use and limit max used.
This change increases the base part of optimumTime at all depths. It also reduces the size of max_scale and thus maximumTime by using a linear scale instead of pow(x, 0.3) and by limiting max_scale to no more than 7 (previously as high as 8 or 9 at very high depths).
Tested using the closedpos book:
STC 10+0.1:
LLR: 2.94 (-2.94,2.94) {-0.50,1.50}
Total: 83696 W: 16813 L: 16508 D: 50375
Ptnml(0-2): 1315, 9649, 19686, 9812, 1386
https://tests.stockfishchess.org/tests/view/5ebfa92de9d85f94dc42989b
LTC 60+0.6:
LLR: 2.95 (-2.94,2.94) {0.25,1.75}
Total: 39384 W: 5868 L: 5582 D: 27934
Ptnml(0-2): 276, 3697, 11489, 3925, 305
https://tests.stockfishchess.org/tests/view/5ec0a6dce9d85f94dc42995a
Test for non-regression:
STC Sudden Death 10+0 :
LLR: 2.94 (-2.94,2.94) {-2.00,0.00}
Total: 111976 W: 25661 L: 25768 D: 60547
Ptnml(0-2): 2567, 13420, 24118, 13319, 2564
https://tests.stockfishchess.org/tests/view/5ec23b3be9d85f94dc429a58
closes https://github.com/official-stockfish/Stockfish/pull/2685
Bench 4395562