[WIP][ENH] Fix coverage for multiprocessed functions

[arnaudbore]

Quick description

Codecov is not covering multiprocessing functions.
https://app.codecov.io/gh/scilus/scilpy/blob/master/scilpy%2Freconst%2Fdivide.py#L266
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Type of change

Check the relevant options.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Provide data, screenshots, command line to test (if relevant)

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Checklist

• My code follows the style guidelines of this project (run autopep8)
• I added relevant citations to scripts, modules and functions docstrings and descriptions
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I moved all functions from the script file (except the argparser and main) to scilpy modules
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.17%. Comparing base (4c2848c) to head (de0060a).
Report is 124 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #927   +/-   ##
=======================================
  Coverage   69.17%   69.17%           
=======================================
  Files         389      389           
  Lines       20963    20963           
  Branches     3233     3233           
=======================================
  Hits        14501    14501           
  Misses       5132     5132           
  Partials     1330     1330           

Components	Coverage Δ
Scripts	71.60% <ø> (ø)
Library	65.05% <ø> (ø)