Unify Movepick Initializer

Passed Non-regression STC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 168704 W: 43524 L: 43455 D: 81725
Ptnml(0-2): 414, 17173, 49076, 17308, 381
https://tests.stockfishchess.org/tests/view/66904b7b5034141ae599a197

Passed Non-regression LTC:
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 120294 W: 30473 L: 30364 D: 59457
Ptnml(0-2): 40, 10974, 38032, 11039, 62
https://tests.stockfishchess.org/tests/view/66905b235034141ae599a223

closes https://github.com/official-stockfish/Stockfish/pull/5477

bench 1459677

src/movepick.h

@@ -160,14 +160,7 @@ class MovePicker {
                const CapturePieceToHistory*,
                const PieceToHistory**,
                const PawnHistory*,
-               Move);
-    MovePicker(const Position&,
-               Move,
-               Depth,
-               const ButterflyHistory*,
-               const CapturePieceToHistory*,
-               const PieceToHistory**,
-               const PawnHistory*);
+               Move killer = Move::none());
     MovePicker(const Position&, Move, int, const CapturePieceToHistory*);
     Move next_move(bool skipQuiets = false);