Try changing StateDiff to be BTreeMap instead of Vec to avoid conversions in between

[yaziciahmet]

Both in native and zk, we constantly change convert one to another to ensure unique keys in the state diff. Main reason we change to Vec is to be able to serialize it. Instead of this, we can have some sort of BTreeMap wrapper structure, which implements its own fast serialization.

[kpp]

Do we really need this issue given that soon we will have statefull stdiff implemented?