Fix definition of predeploy namespace

[geoknee]

Drive-by question:

Has it always been the case that predeploys live in a 1 byte namespace?

I think this is a counterexample https://optimistic.etherscan.io/address/0x4200000000000000000000000000000000000800

[tynes]

This is definitely a bug, there are a total of 2048 predeploys, that is bigger than a 1 byte namespace

[geoknee]

This is definitely a bug, there are a total of 2048 predeploys, that is bigger than a 1 byte namespace

Updated here 51b1497