on EXTCODEHASH load bytecode and check if it is EOF

[rakita]

if EXTCODEHASH target is an account with EOF bytecode, we need to return 0x9dbf3648db8210552e9c4f75c6a1c3057c0ca432043bd648be15fe7be05646f5

This means that extcodehash would need to load account bytecode and check first byte of it.

https://github.com/ipsilon/eof/blob/main/spec/eof.md#modified-behavior

When executed from a legacy contract, if the target account of EXTCODEHASH is an EOF contract,
then it will return 0x9dbf3648db8210552e9c4f75c6a1c3057c0ca432043bd648be15fe7be05646f5
(the hash of EF00, as if that would be the code).