Keep track of whether memory is allocated by Rust's allocator

[keram88]

SMACK should be able to check if Rust's allocator is used on memory originating from a different allocator. For example, a pointer from C allocated with malloc may be obtained through Rust's FFI. It should be an error to then use Rust's dealloc function to free this memory since it cannot be guaranteed that they originate from the same allocator.