JP-3771 and JP-3791: Ramp Fitting Multiprocessing Regression Testing and Read Noise Variance

[kmacdonald-stsci]

Resolves JP-3771 Resolves JP-3771

This PR addresses adding ramp fitting and jump step multiprocessing regression test. The ramp fit multiprocessing regression test revealed a logical bug in the way the read noise variance gets recalculated due to the CHARGELOSS flagging. The original group DQ flagging array, nor the CHARGELOSS flag, were being properly copied to each data sliced used to divide the data in preparation for multiprocessing.

Tasks

• [ ] update or add relevant tests
• [ ] update relevant docstrings and / or docs/ page
• [ ] Does this PR change any API used downstream? (if not, label with no-changelog-entry-needed)
  • [ ] write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types)
  • [ ] run regression tests with this branch installed ("git+https://github.com/<fork>/stcal@<branch>")
  • [ ] jwst regression test
  • [ ] romancal regression test

news fragment change types...

- ``changes/.apichange.rst``: change to public API - ``changes/.bugfix.rst``: fixes an issue - ``changes/.general.rst``: infrastructure or miscellaneous change

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 60.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 86.28%. Comparing base (60bd3b8) to head (20388ec). Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
src/stcal/ramp_fitting/ols_fit.py	60.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #313 +/- ## ========================================== + Coverage 86.21% 86.28% +0.07% ========================================== Files 47 49 +2 Lines 8812 8875 +63 ========================================== + Hits 7597 7658 +61 - Misses 1215 1217 +2 ```

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[kmacdonald-stsci]

Closing to fix multiprocessing bug in the optional results product.