Fixes handling cprnc output

[jasonb5]

• Improves handling of exceptions raised from invoking CPRNC
• Updates get_ts_synopsis, always passes a message back
• Fixes overall status to consider the reason baseline phase fails

Test suite: pytest -v CIME/tests Test baseline: n/a Test namelist changes: n/a Test status: n/a

Fixes n/a User interface changes?: N Update gh-pages html (Y/N)?: N