Stabilize test suite: fix flaky timing tests, and handle Windows reso…

[Dreamsorcerer]

…urce leaks (#11992)

(cherry picked from commit 32924e8)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.28%. Comparing base (d99ba3b) to head (8826895).
⚠️ Report is 1 commits behind head on 3.13.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             3.13   #12076   +/-   ##
=======================================
  Coverage   98.27%   98.28%           
=======================================
  Files         128      128           
  Lines       44528    44536    +8     
  Branches     2426     2426           
=======================================
+ Hits        43761    43770    +9     
  Misses        590      590           
+ Partials      177      176    -1     

Flag	Coverage Δ
CI-GHA	98.16% <96.29%> (+<0.01%)	⬆️
OS-Linux	97.91% <92.59%> (-0.01%)	⬇️
OS-Windows	95.59% <44.44%> (-0.02%)	⬇️
OS-macOS	97.16% <77.77%> (-0.01%)	⬇️
Py-3.10.11	96.70% <81.48%> (+<0.01%)	⬆️
Py-3.10.19	97.18% <92.59%> (-0.02%)	⬇️
Py-3.11.14	97.37% <92.59%> (-0.01%)	⬇️
Py-3.11.9	96.89% <81.48%> (-0.01%)	⬇️
Py-3.12.10	96.98% <77.77%> (+1.79%)	⬆️
Py-3.12.12	97.46% <92.59%> (-0.01%)	⬇️
Py-3.13.12	97.69% <92.59%> (-0.01%)	⬇️
Py-3.14.3	97.61% <55.55%> (-0.03%)	⬇️
Py-3.14.3t	96.71% <55.55%> (-0.03%)	⬇️
Py-3.9.13	96.59% <81.48%> (+<0.01%)	⬆️
Py-3.9.25	97.08% <92.59%> (-0.01%)	⬇️
Py-pypy3.11.13-7.3.20	96.90% <40.74%> (-0.01%)	⬇️
VM-macos	97.16% <77.77%> (-0.01%)	⬇️
VM-ubuntu	97.91% <92.59%> (-0.01%)	⬇️
VM-windows	95.59% <44.44%> (-0.02%)	⬇️

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[codspeed-hq]

Merging this PR will not alter performance

✅ 59 untouched benchmarks

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_{Comparing patchback/backports/3.13/32924e8fa4c9085dcbaf41b3b3c27fc773bfa213/pr-11992 (8826895) with 3.13 (d99ba3b)}