Ensure all memory is deallocated when no longer needed

Some tests don't properly deallocate memory. There tends to be calls to `X_Construct` functions and sometimes no corresponding `X_Destruct` calls. This causes memory leaks.

We should ensure that anywhere memory is allocated (be it with `Xalloc` type calls or using `X_Construct` calls), we should free it up in the appropriate way when it is no longer required.
