Fix clippy warnings.

This commit fixes the current set of (stable) clippy warnings in the repo.

cranelift/codegen/src/licm.rs

@@ -71,7 +71,7 @@ fn create_pre_header(
     domtree: &DominatorTree,
 ) -> Ebb {
     let pool = &mut ListPool::<Value>::new();
-    let header_args_values: Vec<Value> = func.dfg.ebb_params(header).into_iter().cloned().collect();
+    let header_args_values = func.dfg.ebb_params(header).to_vec();
     let header_args_types: Vec<Type> = header_args_values
         .clone()
         .into_iter()