Remove supporting pawns

Tested in no-regression mode

Passed both STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 44957 W: 7984 L: 7903 D: 29070

and LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 12396 W: 1916 L: 1783 D: 8697

Bench: 7907885
Small simplification to passed pawns

Tested in no-regression mode.

Passed both STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28521 W: 5066 L: 4958 D: 18497

And LTC
LLR: 3.04 (-2.94,2.94) [-3.00,1.00]
Total: 21939 W: 3261 L: 3138 D: 15540

bench: 8165681
Generalize shift_bb() to handle double pushes

And use it in evaluate_space.

No functional change.
Merge remote-tracking branch 'upstream/master'