Zero out arrays before use

[apcraig]

PR checklist

• [X] Short (1 sentence) summary of your PR: Zero out a few arrays before use, trapped via snan debug run
• [X] Developer(s): apcraig
• [X] Suggest PR reviewers from list in the column to the right.
• [X] 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?
  • [X] bit for bit
  • [ ] different at roundoff level
  • [ ] more substantial
• Does this PR create or have dependencies on CICE or any other models?
  • [ ] Yes
  • [X] No
• Does this PR add any new test cases?
  • [ ] Yes
  • [X] 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
  • [X] No, does the documentation need to be updated at a later time?
    • [ ] Yes
    • [X] No
• [X] Please provide any additional information or relevant details below:

Related to https://github.com/CICE-Consortium/CICE/pull/560 and https://github.com/CICE-Consortium/CICE/issues/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