Try substituting $crate with super to make verify_std_cmd pass …

…on CI

library/kani_core/src/mem.rs

@@ -312,7 +312,7 @@ macro_rules! kani_mem {
 
  /// A helper to assert `is_initialized` to use it as a part of other predicates.
  fn assert_is_initialized<T: ?Sized>(ptr: *const T) -> bool {
- $crate::check(
+ super::check(
  is_initialized(ptr),
  "Undefined Behavior: Reading from an uninitialized pointer",
  );