Remove duplicate AddOperation to registry (#2664)

Signed-off-by: Matt Kula <matt@theathletic.com>

ethereum/core/src/main/java/org/hyperledger/besu/ethereum/mainnet/MainnetEvmRegistries.java

@@ -155,7 +155,6 @@ abstract class MainnetEvmRegistries {
   private static void registerFrontierOpcodes(
       final OperationRegistry registry, final GasCalculator gasCalculator) {
     registry.put(new AddOperation(gasCalculator));
-    registry.put(new AddOperation(gasCalculator));
     registry.put(new MulOperation(gasCalculator));
     registry.put(new SubOperation(gasCalculator));
     registry.put(new DivOperation(gasCalculator));