Save RNG for generating random storage sampling offsets (#4450)

* Save RNG for generating random storage sampling offsets

* fix clippy

* fix stable-perf

* fix chacha

programs/storage_api/src/storage_instruction.rs

@@ -22,6 +22,7 @@ pub enum StorageInstruction {
         sha_state: Hash,
         slot: u64,
         signature: Signature,
+        proof_index: u64,
     },
     AdvertiseStorageRecentBlockhash {
         hash: Hash,
@@ -109,11 +110,13 @@ pub fn mining_proof(
     sha_state: Hash,
     slot: u64,
     signature: Signature,
+    proof_index: u64,
 ) -> Instruction {
     let storage_instruction = StorageInstruction::SubmitMiningProof {
         sha_state,
         slot,
         signature,
+        proof_index,
     };
     let account_metas = vec![AccountMeta::new(*storage_pubkey, true)];
     Instruction::new(id(), &storage_instruction, account_metas)