Revert "Make forward_model_ok run in its own process"

[oyvindeide]

This reverts commit 9a8441f.

Issue
Resolves #my_issue

Approach
Short description of the approach

Pre review checklist

• Read through the code changes carefully after finishing work
• Make sure tests pass locally (after every commit!)
• Wait for tests in CI to pass (see "checks" below)
• Prepare changes in small commits for more convenient review (optional)
• PR title captures the intent of the changes, and is fitting for release notes.
• Updated documentation
• Ensured new behaviour is tested (opened GUI? screenshots? tried workflows?)
• Commit history is consistent and clean, in line with the contribution guidelines.

Pre merge checklist

• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution
  guidelines.

[xjules]

Revert, revert!

[codecov-commenter]

Codecov Report

Merging #6030 (26144a1) into version-6.0 (c26f2f2) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@               Coverage Diff               @@
##           version-6.0    #6030      +/-   ##
===============================================
+ Coverage        81.90%   81.94%   +0.03%     
===============================================
  Files              350      350              
  Lines            21870    21818      -52     
  Branches           737      737              
===============================================
- Hits             17913    17879      -34     
+ Misses            3704     3686      -18     
  Partials           253      253              

Files Changed	Coverage Δ
src/ert/job_queue/job_queue_node.py	92.00% <100.00%> (+4.69%)	⬆️

... and 2 files with indirect coverage changes

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