Derive gasIncrementAmount from MaxGasEIP1559 and DecayRange. (#850)

* Derive gasIncrementAmount from MaxGasEIP1559 and DecayRange.

* Update default decay range

Signed-off-by: Abdelhamid Bakhta <abdelhamid.bakhta@consensys.net>

config/src/main/java/org/hyperledger/besu/config/experimental/ExperimentalEIPs.java

@@ -69,13 +69,7 @@ public class ExperimentalEIPs {
       hidden = true,
       names = {"--Xeip1559-decay-range"},
       arity = "1")
-  public static Long decayRange = 800000L;
+  public static Long decayRange = 1000000L;
-
-  @Option(
-      hidden = true,
-      names = {"--Xeip1559-gas-increment-amount"},
-      arity = "1")
-  public static Long gasIncrementAmount = 10L;
 
   @Option(
       hidden = true,

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/core/fees/FeeMarket.java

@@ -40,7 +40,6 @@ public interface FeeMarket {
         ExperimentalEIPs.targetGasUsed,
         ExperimentalEIPs.slackCoefficient,
         ExperimentalEIPs.decayRange,
-        ExperimentalEIPs.gasIncrementAmount,
         ExperimentalEIPs.initialBasefee,
         ExperimentalEIPs.perTxGasLimit);
   }

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/core/fees/FeeMarketConfig.java

@@ -18,26 +18,27 @@ public class FeeMarketConfig implements FeeMarket {
   private final long basefeeMaxChangeDenominator;
   private final long targetGasUsed;
   private final long decayRange;
-  private final long gasIncrementAmount;
   private final long initialBasefee;
   private final long perTxGaslimit;
   private final long slackCoefficient;
+  private final long maxGas;
+  private final long gasIncrementAmount;
 
   public FeeMarketConfig(
       final long basefeeMaxChangeDenominator,
       final long targetGasUsed,
       final long slackCoefficient,
       final long decayRange,
-      final long gasIncrementAmount,
       final long initialBasefee,
       final long perTxGaslimit) {
     this.basefeeMaxChangeDenominator = basefeeMaxChangeDenominator;
     this.targetGasUsed = targetGasUsed;
     this.slackCoefficient = slackCoefficient;
     this.decayRange = decayRange;
-    this.gasIncrementAmount = gasIncrementAmount;
     this.initialBasefee = initialBasefee;
     this.perTxGaslimit = perTxGaslimit;
+    this.maxGas = slackCoefficient * targetGasUsed;
+    this.gasIncrementAmount = this.maxGas / 2 / this.decayRange;
   }
 
   @Override
@@ -52,7 +53,7 @@ public class FeeMarketConfig implements FeeMarket {
 
   @Override
   public long getMaxGas() {
-    return slackCoefficient * targetGasUsed;
+    return maxGas;
   }
 
   @Override