Disable rent in flaky test (#12658)

* Disable rent in test

Co-authored-by: Carl Lin <carl@solana.com>

runtime/src/accounts_db.rs

@@ -2396,6 +2396,14 @@ impl AccountsDB {
             }
         }
     }
+
+    #[cfg(test)]
+    pub fn get_append_vec_id(&self, pubkey: &Pubkey, slot: Slot) -> Option<AppendVecId> {
+        let ancestors = vec![(slot, 1)].into_iter().collect();
+        let accounts_index = self.accounts_index.read().unwrap();
+        let result = accounts_index.get(&pubkey, Some(&ancestors), None);
+        result.map(|(list, index)| list[index].1.store_id)
+    }
 }
 
 #[cfg(test)]