Verified SEE pruning for capturing and checking moves.

Patch analyzes field after SEE exchanges concluded with a recapture by
the opponent:
if opponent Queen/Rook/King results under attack after the exchanges, we
consider the move sharp and don't prune it.

Important note:
By accident I forgot to adjust 'occupied' when the king takes part in
the exchanges.
As result of this a move is considered sharp too, when opponent king
apparently can evade check by recapturing.
Surprisingly this seems contribute to patch's strength.

STC:
https://tests.stockfishchess.org/tests/view/640b16132644b62c33947397
LLR: 2.96 (-2.94,2.94) <0.00,2.00>
Total: 116400 W: 31239 L: 30817 D: 54344
Ptnml(0-2): 350, 12742, 31618, 13116, 374

LTC:
https://tests.stockfishchess.org/tests/view/640c88092644b62c3394c1c5
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 177600 W: 47988 L: 47421 D: 82191
Ptnml(0-2): 62, 16905, 54317, 17436, 80

closes https://github.com/official-stockfish/Stockfish/pull/4453

bench: 5012145

src/movepick.cpp

@@ -95,7 +95,7 @@ MovePicker::MovePicker(const Position& p, Move ttm, Value th, const CapturePiece
 
   stage = PROBCUT_TT + !(ttm && pos.capture_stage(ttm)
                              && pos.pseudo_legal(ttm)
-                             && pos.see_ge(ttm, threshold));
+                             && pos.see_ge(ttm, occupied, threshold));
 }
 
 /// MovePicker::score() assigns a numerical value to each move in a list, used
@@ -197,7 +197,7 @@ top:
 
   case GOOD_CAPTURE:
       if (select<Next>([&](){
-                       return pos.see_ge(*cur, Value(-cur->value)) ?
+                       return pos.see_ge(*cur, occupied, Value(-cur->value)) ?
                               // Move losing capture to endBadCaptures to be tried later
                               true : (*endBadCaptures++ = *cur, false); }))
           return *(cur - 1);
@@ -264,7 +264,7 @@ top:
       return select<Best>([](){ return true; });
 
   case PROBCUT:
-      return select<Next>([&](){ return pos.see_ge(*cur, threshold); });
+      return select<Next>([&](){ return pos.see_ge(*cur, occupied, threshold); });
 
   case QCAPTURE:
       if (select<Next>([&](){ return   depth > DEPTH_QS_RECAPTURES