Adjust lowest depth constants to the natural place
Passed STC:
https://tests.stockfishchess.org/tests/view/665ce3f8fd45fb0f907c537f
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 282784 W: 73032 L: 73082 D: 136670
Ptnml(0-2): 680, 31845, 76364, 31851, 652
Recently when I overhauled these comments, Disservin asked why these
were so much lower: they're a relic from when we had a third QS stage at
-5. Now we don't, so fix these to the obvious place.
I was fairly sure it was nonfunctional but ran the nonreg to be double
sure.
closes https://github.com/official-stockfish/Stockfish/pull/5343
Bench: 1057383