allow with_seed functions to accept any bytes, not just UTF-8

[kevinheavey]

The with_seed functions (eg Address::create_with_seed) and WithSeed instruction variants (eg SystemInstruction::CreateAccountWithSeed) all expect &str or String. But they don't do anything that requires UTF-8, and they just convert these values back to bytes.

Two reasons this is bad:

1. Bincode wastes time on UTF-8 validation
2. It would be nice to use arbitrary bytes (such as an Address) as a seed

Breaking changes:

• Address::create_with_seed is technically a breaking change. Changing the type to &(impl AsRef<[u8]> + ?Sized), means it works as before for most people, but breaks for anyone passing create_with_seed itself to a function that expected the seed param to be &str. It's possible that nobody is doing this.
• system-interface, vote-interface and the wasm helpers just change to &[u8] or Vec<u8>

In Agave there would be some small changes to system_processor.rs and vote_processor.rs. Firedancer would need to remove the UTF-8 check. Does this need a SIMD?

[t-nelson]

i don't think there is any rationale for enforcing utf8 here

Does this need a SIMD?

yes. during adoption of the change, upgraded vs not nodes would have differing execution results for non-utf8 inputs

[kevinheavey]

Pre-SIMD discussion here solana-foundation/solana-improvement-documents#378

[kevinheavey]

SIMD: solana-foundation/solana-improvement-documents#390