Ensure all memory is deallocated when no longer needed

[cjheppell]

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.