Add explicit scaling for when the strong side has no pawns

[TheRealGioviok]

Passed STC:

Test  | nopawnendgamescaling
Elo   | 3.62 +- 2.54 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=16MB
LLR   | 2.97 (-2.94, 2.94) [0.00, 3.00]
Games | N: 27256 W: 7653 L: 7369 D: 12234
Penta | [409, 3270, 6101, 3324, 524]

https://ob.cwchess.org/test/1444/

Passed LTC:

Test  | nopawnendgamescaling
Elo   | 3.68 +- 2.46 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=64MB
LLR   | 2.95 (-2.94, 2.94) [0.00, 3.00]
Games | N: 22478 W: 5878 L: 5640 D: 10960
Penta | [141, 2598, 5552, 2778, 170]

https://ob.cwchess.org/test/1445/

Bench: 15576368