vliw benchmark raises Subscript when comparing programs

Calling the `SimStuff.cmprog` function on the results causes a `Subscript` exception to be raised at line 370 of `set-env.sml`.  This call is not part of the actual benchmark run, but is done to test the results.

Note that the original version of the benchmark (see `vliw.sml`) does not call the `cmprog` function, but it also has the same issue.