Add tests to test suite to run run_neon #2438
Description
Rather than pursue #2276 I think we should add a system test that runs a run_neon to setup and run a few cases under run_neon so we know it's working. This will also help with making sure that externals updates don't break run_neon as we saw in #2437. And as discussed here: #2437 (comment) we should add this to the prealpha test list so that new externals updates will be tested with CESM alpha tags and we can find problems sooner.