feat(tests): CREATE failure refunds account state gas to reservoir

Adds six tests in `test_state_gas_create.py` covering every failure
branch in `generic_create` (silent failure, address collision, child
revert, child exceptional halt, code deposit OOG) plus block level
accounting with a mixed success and failure transaction:

  test_create_silent_failure_refunds_state_gas
  test_create_child_revert_refunds_state_gas
  test_create_child_halt_refunds_state_gas
  test_create_mixed_success_and_failure_block_accounting
  test_create_collision_refunds_state_gas
  test_create_code_deposit_oog_refunds_state_gas

All six are strict discriminators of the spec change (24 out of 24
variants fail when the refund is reverted, all pass when applied).
Tests that depend on a narrow gas window (child halt, collision,
code deposit OOG) use a caller wrapper with tight gas tuning so the
probe SSTORE can only succeed via the refunded reservoir. Tests that
verify block header `gas_used` compute the expected value as
`max(tx_regular, tx_state)` defensively from
`factory_code.gas_cost(fork)` so the assertion stays correct if the
underlying constants drift.

Adds `init_code_at_high_bytes` helper to `spec.py` for placing short
init code at the high bytes of a 32 byte memory slot, shared across
the new tests.

Removes `test_code_deposit_oog_reservoir_inflation_detection`
because the new refund behavior intentionally inflates the parent
reservoir on child failure, swamping the ordering signal that test
relied on. Code deposit ordering remains covered by
`test_create_oog_reservoir_inflation_detection`.

Author: spencer-tb

tests/amsterdam/eip8037_state_creation_gas_cost_increase/spec.py

@@ -2,6 +2,17 @@
 
 from dataclasses import dataclass
 
+from execution_testing.vm import Bytecode, Op
+
+
+def init_code_at_high_bytes(
+    init_code: Op | Bytecode | bytes,
+) -> tuple[int, int]:
+    """Return (mstore_value, size) to place init_code at memory[0:size]."""
+    code_bytes = bytes(init_code)
+    size = len(code_bytes)
+    return int.from_bytes(code_bytes, "big") << (256 - 8 * size), size
+
 
 @dataclass(frozen=True)
 class ReferenceSpec: