Refactor accumulator storage/updates

Passed Non-regression STC:
LLR: 2.93 (-2.94,2.94) <-1.75,0.25>
Total: 115840 W: 29983 L: 29854 D: 56003
Ptnml(0-2): 338, 12990, 31149, 13091, 352
https://tests.stockfishchess.org/tests/view/67d0a044166a3e8781d84223

closes https://github.com/official-stockfish/Stockfish/pull/5927

No functional change

src/evaluate.h

@@ -39,6 +39,7 @@ namespace Eval {
 namespace NNUE {
 struct Networks;
 struct AccumulatorCaches;
+class AccumulatorStack;
 }
 
 std::string trace(Position& pos, const Eval::NNUE::Networks& networks);
@@ -47,6 +48,7 @@ int   simple_eval(const Position& pos, Color c);
 bool  use_smallnet(const Position& pos);
 Value evaluate(const NNUE::Networks&          networks,
                const Position&                pos,
+               Eval::NNUE::AccumulatorStack&  accumulators,
                Eval::NNUE::AccumulatorCaches& caches,
                int                            optimism);
 }  // namespace Eval