Add running single point tests on Casper to our standard testing

On Derecho it's better for jobs with less than 128 processors to run on Casper. Eventually it'll probably be best if users can setup, configure, and build on Derecho, and then when they submit it ends up going to Casper rather than Derecho. But, the user's experience is that they are just using Derecho. Having that work, likely will need changes both in CESM and by CISL to get that environment working. But, in the meantime and possibly long term we need to make sure Casper is working for running single point cases. So we need to setup the testlist for Casper and have that as a standard set of tests we run for making tags.