Fix clippy's performance lints (#1286)

* Fix clippy perf lints

* Cargo fmt

* Add  and  to lint rule in Makefile

* Fix some leftover clippy lints

beacon_node/beacon_chain/src/test_utils.rs

@@ -444,7 +444,7 @@ where
         };
 
         let sk = &self.keypairs[proposer_index].sk;
-        let fork = &state.fork.clone();
+        let fork = &state.fork;
 
         let randao_reveal = {
             let epoch = slot.epoch(E::slots_per_epoch());
@@ -605,7 +605,7 @@ where
                             selection_proof.is_aggregator(bc.committee.len(), spec).unwrap_or(false)
                         })
                         .copied()
-                        .expect(&format!(
+                        .unwrap_or_else(|| panic!(
                             "Committee {} at slot {} with {} attesting validators does not have any aggregators",
                             bc.index, state.slot, bc.committee.len()
                         ));