Add blockToClosure function

This function lists all closures in a block

The TSO decoding logic is wrong, the format of a TSO closure depends on the OS and also on if the profiling RTS is being used:

    StgWord32  tot_stack_size;

#if defined(TICKY_TICKY)
    /* TICKY-specific stuff would go here. */
#endif
#if defined(PROFILING)
    StgTSOProfInfo prof;
#endif
#if defined(mingw32_HOST_OS)
    StgWord32 saved_winerror;
#endif

} *StgTSOPtr; // StgTSO defined in rts/Types.h