use intrinsic gas cost calculator

Signed-off-by: Ignacio Hagopian <jsign.uy@gmail.com>

Author: jsign

tests/zkevm/test_worst_compute.py

@@ -10,7 +10,8 @@
 import pytest
 
 from ethereum_test_forks import Fork
-from ethereum_test_tools import Alloc, Block, BlockchainTestFiller, Environment, Transaction
+from ethereum_test_tools import (Alloc, Block, BlockchainTestFiller,
+                                 Environment, Transaction)
 from ethereum_test_tools.vm.opcode import Opcodes as Op
 
 REFERENCE_SPEC_GIT_PATH = "TODO"
@@ -41,8 +42,8 @@ def test_worst_keccak(
     env = Environment(gas_limit=gas_limit)
 
     # Intrinsic gas cost is paid once.
-    tx_intrinsic_gas = 21_000
-    available_gas = gas_limit - tx_intrinsic_gas
+    intrinsic_gasc_calculator = fork.transaction_intrinsic_cost_calculator()
+    available_gas = gas_limit - intrinsic_gasc_calculator()
 
     gsc = fork.gas_costs()
     mem_exp_gas_calculator = fork.memory_expansion_gas_calculator()