slightly nudge choices towards less sequences

also slightly improve some strange detrimental corner cases.

lib/compress/zstd_opt.c

@@ -282,6 +282,8 @@ ZSTD_getMatchPrice(U32 const offset,
         price += (ML_bits[mlCode] * BITCOST_MULTIPLIER) + (optPtr->matchLengthSumBasePrice - WEIGHT(optPtr->matchLengthFreq[mlCode], optLevel));
     }
 
+    price += BITCOST_MULTIPLIER / 5;   /* heuristic : make matches a bit more costly to favor less sequences -> faster decompression speed */
+
     DEBUGLOG(8, "ZSTD_getMatchPrice(ml:%u) = %u", matchLength, price);
     return price;
 }