chore(tests): update gas cost configuration for clz (#1887)

Author: LouisTsai-Csie

tests/osaka/eip7939_count_leading_zeros/test_count_leading_zeros.py

@@ -117,7 +117,7 @@ def test_clz_gas_cost(state_test: StateTestFiller, pre: Alloc, fork: Fork):
             CodeGasMeasure(
                 code=Op.CLZ(Op.PUSH1(1)),
                 extra_stack_items=1,
-                overhead_cost=fork.gas_costs().G_LOW,
+                overhead_cost=fork.gas_costs().G_VERY_LOW,
             ),
         ),
         storage={"0x00": "0xdeadbeef"},
@@ -126,7 +126,7 @@ def test_clz_gas_cost(state_test: StateTestFiller, pre: Alloc, fork: Fork):
     tx = Transaction(to=contract_address, sender=sender, gas_limit=200_000)
     post = {
         contract_address: Account(  # Cost measured is CLZ + PUSH1
-            storage={"0x00": fork.gas_costs().G_VERY_LOW}
+            storage={"0x00": fork.gas_costs().G_LOW}
         ),
     }
     state_test(pre=pre, post=post, tx=tx)