Feature Gate: separate durable nonce and blockhash domains

[behzadnouri]

Description

AdvanceNonceAccount instruction updates nonce to blockhash. This makes it
possible that a durable transaction is executed twice both as a normal
transaction and a nonce transaction if it uses blockhash (as opposed to nonce)
for its recent_blockhash field.

#25744 prevents this double execution by separating nonce and blockhash
domains; when advancing nonce account, blockhash is hashed with a fixed string.
As a result a blockhash cannot be a valid nonce value; and if transaction was
once executed as a normal transaction it cannot be re-executed as a durable
transaction again and vice-versa.

Feature ID

Gea3ZkK2N4pHuVZVxWcnAtS6UEDdyumdYt4pFcKjA3ar

Activation Method

Single Core Contributor

Min Release Versions

v1.9.29, v1.10.24

Testnet Activation Epoch

330

Devnet Activation Epoch

327

Mainnet-Beta Activation Epoch

320