Allow for differences in sign of zeros when checking OM3 restart repro

[dougiesquire]

This PR allows for differences in sign of zeros when checking OM3 restart repro. Specifically, checksums are allowed to differ by 8 in the first hex digit. See the following issues for motivation and context:

• ACCESS-OM3: checksums in MOM6 restart file are unreliable #155
• Restart repro failure due to differently signed zeros in restart arrays access-om3-configs#823

Tests are added for the check_checksums_over_restarts method.

Closes #155

[dougiesquire]

Tests pass locally. Test failure is not related to something I have modified:

 ImportError while importing test module '/home/runner/work/model-config-tests/model-config-tests/tests/config_tests/qa/test_test_access_esm1p5_config.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/hostedtoolcache/Python/3.11.14/x64/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
tests/config_tests/qa/test_test_access_esm1p5_config.py:4: in <module>
    from tests.common import RESOURCES_DIR
E   ModuleNotFoundError: No module named 'tests.common'

[codecov]

Codecov Report

❌ Patch coverage is 85.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.39%. Comparing base (62cedf8) to head (b881d91).
⚠️ Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
src/model_config_tests/models/accessom3.py	85.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #188       +/-   ##
===========================================
- Coverage   81.49%   68.39%   -13.10%     
===========================================
  Files          20       14        -6     
  Lines        1194      829      -365     
===========================================
- Hits          973      567      -406     
- Misses        221      262       +41     

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[minghangli-uni]

model-config-tests -m repro_restart
Test session starts (platform: linux, Python 3.11.0, pytest 8.3.4, pytest-sugar 1.0.0)
rootdir: /g/data/tm70/ml0072/COMMON/git_repos/model-config-tests
configfile: pyproject.toml
plugins: anyio-4.9.0, sugar-1.0.0, cov-6.0.0, hypothesis-6.57.1
collected 58 items / 57 deselected / 1 selected                                                                                                                                                      

 src/model_config_tests/config_tests/test_bit_reproducibility.py ✓                                                                                                                     100% ██████████

Results (478.10s (0:07:58)):
       1 passed
      57 deselected

LGTM. Thanks @dougiesquire