Avoid Unstable Sort (#12455)

* dont use unstable sort

* remove comment

* add clippy rule

substrate/primitives/npos-elections/fuzzer/src/common.rs

@@ -80,7 +80,7 @@ pub fn generate_random_npos_inputs(
 		}
 		candidates.push(id);
 	}
-	candidates.sort_unstable();
+	candidates.sort();
 	candidates.dedup();
 	assert_eq!(candidates.len(), candidate_count);
 
@@ -99,11 +99,11 @@ pub fn generate_random_npos_inputs(
 
 		let mut chosen_candidates = Vec::with_capacity(n_candidates_chosen);
 		chosen_candidates.extend(candidates.choose_multiple(&mut rng, n_candidates_chosen));
-		chosen_candidates.sort_unstable();
+		chosen_candidates.sort();
 		voters.push((id, vote_weight, chosen_candidates));
 	}
 
-	voters.sort_unstable();
+	voters.sort();
 	voters.dedup_by_key(|(id, _weight, _chosen_candidates)| *id);
 	assert_eq!(voters.len(), voter_count);