Remove killer move

[87flowers]

Passes STC nonreg:

Test  | rm-killer
Elo   | 1.21 +- 2.94 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=16MB
LLR   | 2.95 (-2.94, 2.94) [-4.50, 0.50]
Games | N: 17298 W: 4082 L: 4022 D: 9194
Penta | [164, 2088, 4095, 2128, 174]

https://clockworkopenbench.pythonanywhere.com/test/962/

Passes LTC nonreg:

Test  | rm-killer
Elo   | 0.14 +- 2.02 (95%)
SPRT  | 40.0+0.40s Threads=1 Hash=64MB
LLR   | 3.03 (-2.94, 2.94) [-4.50, 0.50]
Games | N: 32404 W: 7155 L: 7142 D: 18107
Penta | [191, 3860, 8091, 3865, 195]

https://clockworkopenbench.pythonanywhere.com/test/967/

Bench: 11674122