Simplification: last capture extension

Simplification: last capture extension

The code for last capture extension can be removed in current master.

Passed STC
LLR: 2.95 (-2.94,2.94) {-1.00,0.20}
Total: 85024 W: 7754 L: 7707 D: 69563
Ptnml(0-2): 293, 5991, 29914, 6004, 310
https://tests.stockfishchess.org/tests/view/607690f1814175337896068f

Passed LTC
LLR: 2.96 (-2.94,2.94) {-0.70,0.20}
Total: 39880 W: 1503 L: 1453 D: 36924
Ptnml(0-2): 17, 1281, 17293, 1333, 16
https://tests.stockfishchess.org/tests/view/6076ccbe814175337896069e

Closes https://github.com/official-stockfish/Stockfish/pull/3430

Bench: 4202264