Update Icepack to 4c42a82, non bit-for-bit changes

[apcraig]

PR checklist

• Short (1 sentence) summary of your PR:
  Update Icepack to 4c42a82 and remove two tests
• 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.
  Not bit-for-bit due to tr_aero fix in Icepack (Old aerosol bug fix (tr_aero). Icepack#330) and snow melt bug fix (Snow melt computation bug. Icepack#328)
  Full test results on cheyenne are here, https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#6a9672fb5697994e77c1404eba59420791f7326c (with failing tests) and https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#4b963104daaabb25bd0f5f783cfa46c4549b16e3 (with 2 tests removed).
  Snow melt computation bug. Icepack#328 documents QC test results which pass for the snow melt bug fix. Old aerosol bug fix (tr_aero). Icepack#330 documents QC test results which pass for the tr_aero bug fix.
• 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 Icepack or any other models?
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes, removes two test cases for iobinary with bathymetry netcdf file that broke a few commits back (as expected).
  • 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/. A test build of the technical docs will be performed as part of the PR testing.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please provide any additional information or relevant details below:

Incorporates two important bug fixes from Icepack that are not bit-for-bit,

• tr_aero fix (Old aerosol bug fix (tr_aero). Icepack#330)
• snow melt bug fix (Snow melt computation bug. Icepack#328)

Also removes two tests that are failing and will not fix. With recent updates to NETCDF implementation, configurations with iobinary that have bathymetry on will fail (as they should). These tests were removed.

[dabail10]

Do we want to bring both in at once? Maybe since we are not tagging them, it doesn't matter?

[apcraig]

I'm happy to bring them in separately, although I'm not sure it provides much advantage. We could demonstrate how each Icepack change separately changes answers, but the Icepack PRs largely do that already as they were tested in CICE independently there. If others think we should separate, just let me know, and I'll take care of it.

[dabail10]

Point taken. I have tested the answer changes in standalone Icepack as well as in CICE individually. Both pass the QC control tests. So, I am fine with these going into CICE together if others are.

[eclare108213]

I'm fine with merging all of this together.