TxSelector Coord fees & Nonces checks & other

- Add missing Fees to CoordAccounts after processing PoolL2Txs
- Add Nonces checks for L2Txs (txs with incorrect nonces not included
in the selection)
- Add missing MakeCheckpoint() at the LocalAccountsDB once the
selection is done
- Add TxSelector test of full flow using Til.SetBlockchainMinimumFlow0
checking balances & parameters

test/til/txs.go

@@ -674,6 +674,15 @@ func (tc *Context) generatePoolL2Txs() ([]common.PoolL2Tx, error) {
 	return txs, nil
 }
 
+// RestartNonces sets all the Users.Accounts.Nonces to 0
+func (tc *Context) RestartNonces() {
+	for name, user := range tc.Users {
+		for tokenID := range user.Accounts {
+			tc.Users[name].Accounts[tokenID].Nonce = common.Nonce(0)
+		}
+	}
+}
+
 // generateKeys generates BabyJubJub & Address keys for the given list of user
 // names in a deterministic way. This means, that for the same given
 // 'userNames' in a certain order, the keys will be always the same.