Add zki.ISAccFeeOut generation for circuits compat

- add IntermediateStates AccFeeOut correct generation for circuits
compatibility at ZKInputs
- Fix formatAccumulatedFees
- organize ZKInputs tests to check compatibility with Circom circuits
- Add TestZKInputs2
    - which checks ZKInputs for 4 L1 txs + 2 L2Txs with fees
    - tested with Hermez Circom circuits

db/statedb/txprocessors.go

@@ -240,8 +240,8 @@ func (s *StateDB) ProcessTxs(ptc ProcessTxsConfig, coordIdxs []common.Idx, l1use
 			}
 			s.zki.Metadata.L2TxsData = append(s.zki.Metadata.L2TxsData, l2TxData)
 
-			if s.i < nTx-1 {
 			// Intermediate States
+			if s.i < nTx-1 {
 				s.zki.ISOutIdx[s.i] = s.idx.BigInt()
 				s.zki.ISStateRoot[s.i] = s.mt.Root().BigInt()
 				s.zki.ISAccFeeOut[s.i] = formatAccumulatedFees(collectedFees, s.zki.FeePlanTokens)
@@ -268,6 +268,7 @@ func (s *StateDB) ProcessTxs(ptc ProcessTxsConfig, coordIdxs []common.Idx, l1use
 			if i < int(ptc.MaxTx)-1 {
 				s.zki.ISOutIdx[i] = s.idx.BigInt()
 				s.zki.ISStateRoot[i] = s.mt.Root().BigInt()
+				s.zki.ISAccFeeOut[i] = formatAccumulatedFees(collectedFees, s.zki.FeePlanTokens)
 			}
 			if i >= s.i {
 				s.zki.TxCompressedData[i] = new(big.Int).SetBytes(common.SignatureConstantBytes)

db/statedb/utils.go

@@ -170,7 +170,7 @@ func formatAccumulatedFees(collectedFees map[common.TokenID]*big.Int, orderToken
 	for i := 0; i < len(orderTokenIDs); i++ {
 		tokenID := common.TokenIDFromBigInt(orderTokenIDs[i])
 		if _, ok := collectedFees[tokenID]; ok {
-			accFeeOut[i] = collectedFees[tokenID]
+			accFeeOut[i] = new(big.Int).Set(collectedFees[tokenID])
 		} else {
 			accFeeOut[i] = big.NewInt(0)
 		}