Refactor: Removes Rc from Refcell<AccountSharedData> in the program-runtime (#21927)

* Removes Rc from Rc<RefCell<AccountSharedData>> in the program-runtime.

* Adjusts tests in bpf_loader, system_instruction_processor, config_processor, vote_instruction and stake_instruction

runtime/src/bank.rs

@@ -3403,11 +3403,10 @@ impl Bank {
     /// Converts Accounts into RefCell<AccountSharedData>, this involves moving
     /// ownership by draining the source
     fn accounts_to_refcells(accounts: &mut TransactionAccounts) -> TransactionAccountRefCells {
-        let account_refcells: Vec<_> = accounts
+        accounts
             .drain(..)
-            .map(|(pubkey, account)| (pubkey, Rc::new(RefCell::new(account))))
-            .collect();
-        account_refcells
+            .map(|(pubkey, account)| (pubkey, RefCell::new(account)))
+            .collect()
     }
 
     /// Converts back from RefCell<AccountSharedData> to AccountSharedData, this involves moving
@@ -3415,17 +3414,10 @@ impl Bank {
     fn refcells_to_accounts(
         accounts: &mut TransactionAccounts,
         mut account_refcells: TransactionAccountRefCells,
-    ) -> std::result::Result<(), TransactionError> {
+    ) {
         for (pubkey, account_refcell) in account_refcells.drain(..) {
-            accounts.push((
-                pubkey,
-                Rc::try_unwrap(account_refcell)
-                    .map_err(|_| TransactionError::AccountBorrowOutstanding)?
-                    .into_inner(),
-            ))
+            accounts.push((pubkey, account_refcell.into_inner()))
         }
-
-        Ok(())
     }
 
     /// Get any cached executors needed by the transaction
@@ -3641,13 +3633,10 @@ impl Bank {
                             });
                         inner_instructions.push(inner_instruction_list);
 
-                        if let Err(e) = Self::refcells_to_accounts(
+                        Self::refcells_to_accounts(
                             &mut loaded_transaction.accounts,
                             account_refcells,
-                        ) {
-                            warn!("Account lifetime mismanagement");
-                            process_result = Err(e);
-                        }
+                        );
 
                         if process_result.is_ok() {
                             self.update_executors(executors);

runtime/src/message_processor.rs

@@ -202,19 +202,19 @@ mod tests {
             process_instruction: mock_system_process_instruction,
         }];
 
-        let program_account = Rc::new(RefCell::new(create_loadable_account_for_test(
-            "mock_system_program",
-        )));
         let accounts = vec![
             (
                 solana_sdk::pubkey::new_rand(),
-                AccountSharedData::new_ref(100, 1, &mock_system_program_id),
+                RefCell::new(AccountSharedData::new(100, 1, &mock_system_program_id)),
             ),
             (
                 solana_sdk::pubkey::new_rand(),
-                AccountSharedData::new_ref(0, 1, &mock_system_program_id),
+                RefCell::new(AccountSharedData::new(0, 1, &mock_system_program_id)),
+            ),
+            (
+                mock_system_program_id,
+                RefCell::new(create_loadable_account_for_test("mock_system_program")),
             ),
-            (mock_system_program_id, program_account),
         ];
         let program_indices = vec![vec![2]];
 
@@ -406,19 +406,19 @@ mod tests {
             process_instruction: mock_system_process_instruction,
         }];
 
-        let program_account = Rc::new(RefCell::new(create_loadable_account_for_test(
-            "mock_system_program",
-        )));
         let accounts = vec![
             (
                 solana_sdk::pubkey::new_rand(),
-                AccountSharedData::new_ref(100, 1, &mock_program_id),
+                RefCell::new(AccountSharedData::new(100, 1, &mock_program_id)),
             ),
             (
                 solana_sdk::pubkey::new_rand(),
-                AccountSharedData::new_ref(0, 1, &mock_program_id),
+                RefCell::new(AccountSharedData::new(0, 1, &mock_program_id)),
+            ),
+            (
+                mock_program_id,
+                RefCell::new(create_loadable_account_for_test("mock_system_program")),
             ),
-            (mock_program_id, program_account),
         ];
         let program_indices = vec![vec![2]];
 
@@ -539,13 +539,13 @@ mod tests {
             process_instruction: mock_process_instruction,
         }];
 
-        let secp256k1_account = AccountSharedData::new_ref(1, 0, &native_loader::id());
-        secp256k1_account.borrow_mut().set_executable(true);
-        let mock_program_account = AccountSharedData::new_ref(1, 0, &native_loader::id());
-        mock_program_account.borrow_mut().set_executable(true);
+        let mut secp256k1_account = AccountSharedData::new(1, 0, &native_loader::id());
+        secp256k1_account.set_executable(true);
+        let mut mock_program_account = AccountSharedData::new(1, 0, &native_loader::id());
+        mock_program_account.set_executable(true);
         let accounts = vec![
-            (secp256k1_program::id(), secp256k1_account),
-            (mock_program_id, mock_program_account),
+            (secp256k1_program::id(), RefCell::new(secp256k1_account)),
+            (mock_program_id, RefCell::new(mock_program_account)),
         ];
 
         let message = Message::new(