Fix tiny error in test_call_and_callcode_gas_calculation.

Author: evgenyzdanovich

tests/frontier/opcodes/test_call_and_callcode_gas_calculation.py

@@ -23,6 +23,7 @@
        verify whether the provided gas was sufficient or insufficient.
 """
 
+import random
 from typing import Dict
 
 import pytest
@@ -72,7 +73,10 @@ def callee_code(callee_opcode: Op) -> Bytecode:
         GAS <- value doesn't matter
         CALL/CALLCODE.
     """
-    return callee_opcode(Op.GAS(), 0xFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, 1, 0, 0, 0, 0)
+    # The address needs to be random,
+    # otherwise the calculations (empty_account_cost) are incorrect.
+    address = f"0x{random.getrandbits(160):040x}"
+    return callee_opcode(Op.GAS(), address, 1, 0, 0, 0, 0)
 
 
 @pytest.fixture