chore: Deep-clone Case instances before passing to check functions

[Stranger6667]

No description provided.

[codecov-commenter]

Codecov Report

Merging #1419 (f76e631) into master (4a43cfe) will decrease coverage by 0.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1419      +/-   ##
==========================================
- Coverage   99.19%   99.10%   -0.10%     
==========================================
  Files          84       84              
  Lines        6470     6476       +6     
  Branches     1136     1108      -28     
==========================================
  Hits         6418     6418              
- Misses         26       29       +3     
- Partials       26       29       +3     

Flag	Coverage Δ
unittests	99.08% <100.00%> (-0.08%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/schemathesis/models.py	99.05% <100.00%> (ø)
src/schemathesis/runner/impl/core.py	97.81% <100.00%> (+<0.01%)	⬆️
src/schemathesis/specs/openapi/validation.py	76.47% <0.00%> (-11.77%)	⬇️
src/schemathesis/_compat.py	82.60% <0.00%> (-6.29%)	⬇️
src/schemathesis/cli/callbacks.py	98.33% <0.00%> (-1.67%)	⬇️
src/schemathesis/utils.py	98.63% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 4a43cfe...f76e631. Read the comment docs.