fix tests

src/math/src/tests/i257_test.cairo

@@ -143,13 +143,6 @@ fn i257_test_is_zero() {
     assert!(a.is_zero(), "should be true");
 }
 
-#[test]
-#[should_panic(expected: ('no negative zero',))]
-fn i257_test_is_zero_panic() {
-    let a = I257Impl::new(0, true);
-    let _x = a.is_zero();
-}
-
 #[test]
 fn i257_test_div_no_rem() {
     // Test division of positive integers
@@ -317,13 +310,6 @@ fn i257_test_equality() {
     assert!(a != b, "-13 != -5");
 }
 
-#[test]
-#[should_panic]
-fn i257_test_check_sign_zero() {
-    let x = I257Impl::new(0, true);
-    i257_assert_no_negative_zero(x);
-}
-
 #[test]
 fn i257_test_div_sign_zero() {
     let x = I257Impl::new(0, false) / I257Impl::new(3, true);