feat(tests): add invalid BAL tests for spurious block_access_index

tests/amsterdam/eip7928_block_level_access_lists/test_cases.md

@@ -118,3 +118,6 @@
 | `test_bal_4788_selfdestruct_to_beacon_root` | Ensure BAL captures `SELFDESTRUCT` to beacon root address alongside system call storage writes | Single block: Pre-execution system call writes beacon root to storage. Transaction: Alice calls contract (pre-funded with 100 wei) that selfdestructs with `BEACON_ROOTS_ADDRESS` as beneficiary. | BAL **MUST** include at `block_access_index=0`: `BEACON_ROOTS_ADDRESS` with `storage_changes` (timestamp and root slots from system call). At `block_access_index=1`: Alice with `nonce_changes`, contract with `balance_changes` (100→0), `BEACON_ROOTS_ADDRESS` with `balance_changes` (receives 100 wei). | ✅ Completed |
 | `test_bal_7702_double_auth_reset_minimal` | Ensure BAL tracks multiple 7702 nonce increments but filters net-zero code change | Single transaction contains two EIP-7702 authorizations for `Alice`: (1) first auth sets delegation `0xef0100\|\|Oracle`, (2) second auth clears delegation back to empty. Transaction sends 10 wei to `Bob`. Two variants: (a) Self-funded: `Alice` is tx sender (one tx nonce bump + two auth bumps → nonce 0→3). (b) Sponsored: `Relayer` is tx sender (`Alice` only in auths → nonce 0→2 for `Alice`, plus one nonce bump for `Relayer`). | Variant (a): BAL **MUST** include `Alice` with `nonce_changes` 0→3. Variant (b): BAL **MUST** include `Alice` with `nonce_changes` 0→2 and `Relayer` with its own `nonce_changes`. For both variants, BAL **MUST NOT** include `code_changes` for `Alice` (net code is empty), **MUST** include `Bob` with `balance_changes` (receives 10 wei), and `Oracle` **MUST NOT** appear in BAL. | 🟡 Planned |
 | `test_bal_selfdestruct_send_to_sender` | Ensure BAL tracks SELFDESTRUCT sending all funds back to the tx sender (no burn) | Pre-state: contract `C` exists from a prior transaction with non-empty code and balance = 100 wei. EOA `Alice` sends a transaction calling `C`. `C`’s code executes `SELFDESTRUCT(Alice)`. Under EIP-6780, because `C` was not created in this transaction, SELFDESTRUCT does not delete code or storage; it only transfers the entire 100 wei balance from `C` to `Alice`. Final post-state: `C` still exists with the same code and balance = 0; `Alice`’s balance increased by 100 wei (ignoring gas for this test). | BAL **MUST** include `Alice` with `nonce_changes` (tx sender) and `balance_changes` reflecting receipt of 100 wei, and **MUST** include `C` with `balance_changes` 100→0 and no `code_changes`. BAL **MUST NOT** include any other accounts. This test ensures SELFDESTRUCT-to-sender is modeled as a pure value transfer (no burn, no code deletion). | 🟡 Planned |
+| `test_bal_spurious_entry_index_plus_2_with_cross_tx_read`  | Ensure clients reject BALs containing a spurious entry at `bal_index = len(transactions)+2`, even if its slot is legitimately read elsewhere in the block    | Block with `N` txs. BAL is modified to include an extra `StorageKey` entry with `block_access_index = N+2` for `(VictimContract, slot=0x01)`. Additionally include another tx in the same block that performs `SLOAD(VictimContract, 0x01)` (legitimate read).         | Block **MUST** be rejected with `INVALID_BLOCK_ACCESS_LIST` exception. Clients **MUST** validate that every `block_access_index` in BAL is in-range (≤ `N` plus any allowed system ops), and **MUST NOT** accept out-of-range indices even if the `(address, slot)` appears elsewhere legitimately. | 🟡 Planned |
+| `test_bal_spurious_entry_index_plus_2_with_cross_tx_write` | Ensure clients reject BALs containing a spurious entry at `bal_index = len(transactions)+2`, even if its slot is legitimately written elsewhere in the block | Block with `N` txs. BAL is modified to include an extra `StorageKey` entry with `block_access_index = N+2` for `(VictimContract, slot=0x01)`. Additionally include another tx in the same block that performs `SSTORE(VictimContract, 0x01, 0x42)` (legitimate write). | Block **MUST** be rejected with `INVALID_BLOCK_ACCESS_LIST` exception. Clients **MUST** validate `block_access_index` bounds and reject spurious indices regardless of whether the referenced `(address, slot)` is otherwise accessed or mutated in the block.                                      | 🟡 Planned |
+| `test_bal_spurious_entry_index_plus_2_no_other_txs`        | Ensure clients reject BALs containing a spurious entry at `bal_index = len(transactions)+2` when no other transaction touches the referenced slot            | Block with `N` txs that do not access `(VictimContract, slot=0x01)`. BAL is modified to include an extra `StorageKey` entry with `block_access_index = N+2` for `(VictimContract, slot=0x01)`.                                                                         | Block **MUST** be rejected with `INVALID_BLOCK_ACCESS_LIST` exception. Clients **MUST** reject any BAL that contains out-of-range `block_access_index` values, independent of access patterns in the executed block.                                                                                | 🟡 Planned |