dev: ensure consistency in EVM storage

[enitrat]

In CairoZero, the address of an EVM storage is computed as

    // @notice Compute the storage address of the given key when the storage var interface is
    //         Account_storage(key: Uint256)
    // @dev    Just the generated addr method when compiling the account_contract
    func _storage_addr{pedersen_ptr: HashBuiltin*, range_check_ptr}(key: Uint256*) -> (res: felt) {
        let res = 0x0127c52d6fa812547d8a5b435341b8c12e82048913e7193c0e318e8a6642876d;
        let (res) = hash2{hash_ptr=pedersen_ptr}(res, cast(key, felt*)[0]);
        let (res) = hash2{hash_ptr=pedersen_ptr}(res, cast(key, felt*)[1]);
        let (res) = normalize_address(addr=res);
        return (res=res);
    }

Ensure that

        fn write_storage(ref self: ContractState, key: u256, value: u256) {
            self.ownable.assert_only_owner();
            self.Account_storage.write(key, value);
        }

is computing the same key and compatibility is kept.