Zero out arrays before use

[apcraig]

PR checklist

• Short (1 sentence) summary of your PR:
  Zero out a few arrays before use, trapped via snan debug run
• Developer(s):
  apcraig
• Suggest PR reviewers from list in the column to the right.
• Please copy the PR test results link or provide a summary of testing completed below.
  full test suite run on cheyenne, bit-for-bit. https://github.com/CICE-Consortium/Test-Results/wiki/icepack_by_hash_forks#213a227010291e0a6dfd4a5f9c58d1c2f46c5e48
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on CICE or any other models?
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes
  • No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please provide any additional information or relevant details below:

Related to CICE-Consortium/CICE#560 and CICE-Consortium/CICE#247

[apcraig]

This passes all testing on cheyenne, bit-for-bit, with all compilers in Icepack and CICE, but GHActions is unhappy with one test (swccsm3) and aborts. As a result, I am going to close this PR without merging and revisit again later.

[phil-blain]

For reference, here is the output from the failed test:
https://github.com/CICE-Consortium/Icepack/pull/354/checks#step:13:359

[dabail10]

This looks fine. I somehow thought these were initialized before the call to icepack_step_radiation and hence the intent(inout). Perhaps these should just be intent(out)?