Retire loose enemies bonus

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 44727 W: 7943 L: 7862 D: 28922

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 148343 W: 19044 L: 19088 D: 110211

Bench: 5669076

Closes official-stockfish#1005

src/evaluate.cpp

@@ -190,7 +190,6 @@ namespace {
   const Score OtherCheck          = S(10, 10);
   const Score CloseEnemies        = S( 7,  0);
   const Score PawnlessFlank       = S(20, 80);
-  const Score LooseEnemies        = S( 0, 25);
   const Score ThreatByHangingPawn = S(71, 61);
   const Score ThreatByRank        = S(16,  3);
   const Score Hanging             = S(48, 27);
@@ -515,11 +514,6 @@ namespace {
     Bitboard b, weak, defended, safeThreats;
     Score score = SCORE_ZERO;
 
-    // Small bonus if the opponent has loose pawns or pieces
-    if (   (pos.pieces(Them) ^ pos.pieces(Them, QUEEN, KING))
-        & ~(ei.attackedBy[Us][ALL_PIECES] | ei.attackedBy[Them][ALL_PIECES]))
-        score += LooseEnemies;
-
     // Non-pawn enemies attacked by a pawn
     weak = (pos.pieces(Them) ^ pos.pieces(Them, PAWN)) & ei.attackedBy[Us][PAWN];