fix: minor

Author: gilcu3

src/ecdsa/robust_ecdsa/presign.rs

@@ -403,10 +403,7 @@ mod test {
 
         assert!(result.len() == 5);
         // testing that big_r is the same accross participants
-        assert_eq!(result[0].1.big_r, result[1].1.big_r);
-        assert_eq!(result[1].1.big_r, result[2].1.big_r);
-        assert_eq!(result[2].1.big_r, result[3].1.big_r);
-        assert_eq!(result[3].1.big_r, result[4].1.big_r);
+        assert!(result.windows(2).all(|w| w[0].1.big_r == w[1].1.big_r));
 
         insta::assert_json_snapshot!(result);
     }