fix clippy::redundant_pattern_matching in tests

Author: hellow554

tests/quick.rs

@@ -258,12 +258,12 @@ where
         let mut it = get_it();
 
         for _ in 0..(counts.len() - 1) {
-            if let None = it.next() {
+            if it.next().is_none() {
                 panic!("Iterator shouldn't be finished, may not be deterministic");
             }
         }
 
-        if let None = it.next() {
+        if it.next().is_none() {
             break 'outer;
         }