Remove tests that are no longer feasible

library/kani/src/mem.rs

@@ -65,6 +65,8 @@ where
     if sz == 0 {
         true // ZST pointers are always valid
     } else {
+        // Note that this branch can't be tested in concrete execution as `is_read_ok` needs to be
+        // stubbed.
         crate::assert(
             is_read_ok(thin_ptr, sz),
             "Expected valid pointer, but found dangling pointer",
@@ -247,18 +249,6 @@ mod tests {
         assert_valid_ptr(vec_ptr);
     }
 
-    #[test]
-    #[should_panic(expected = "Expected valid pointer, but found dangling pointer")]
-    fn test_dangling_char() {
-        test_dangling_of_t::<char>();
-    }
-
-    #[test]
-    #[should_panic(expected = "Expected valid pointer, but found dangling pointer")]
-    fn test_dangling_slice() {
-        test_dangling_of_t::<&str>();
-    }
-
     #[test]
     #[should_panic(expected = "Expected valid pointer, but found `null`")]
     fn test_null_fat_ptr() {