check_inputdata

I'm not sure if this belongs here or in [NCAR/MOM6](https://github.com/NCAR/MOM6) (or maybe in [ESMCI/cime](https://github.com/ESMCI/cime)?), but I tried to port my MOM6+MARBL branch to `izumi` and forgot to copy my inputdata files over -- everything is stashed in `/glade/work/mlevy` until I finish testing and we decide on a final fileset.

Anyway, I didn't realize I had forgotten to copy these files over, and `case.submit` didn't complain about this missing files... instead, it started the run and hung during init. Looking at the logs, it crashed when calling `MOM_temp_salt_initialize_from_Z()` so it didn't even try to read the non-existent files (which leads to a question unrelated to this particular issue, but does CESM+MOM run on izumi yet?).

edit to add: the crash in `MOM_temp_salt_initialize_from_Z()` comes from a sandbox based on `cesm2_3_alpha02d` using the intel compiler; when I tried the nag compiler I got build errors (in FMS, I believe)