test_runner: use primordials in utils.js

[Ayoub-Mabrouk]

Replace native array method (.push) with primordials (ArrayPrototypePush) in lib/internal/test_runner/utils.js for consistency and security. This improves protection against prototype pollution and aligns with the primordials pattern used throughout the codebase.

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 88.53%. Comparing base (05d6b9b) to head (e2fec2d).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/utils.js	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61204      +/-   ##
==========================================
- Coverage   88.53%   88.53%   -0.01%     
==========================================
  Files         703      703              
  Lines      208599   208599              
  Branches    40229    40225       -4     
==========================================
- Hits       184685   184676       -9     
- Misses      15939    15942       +3     
- Partials     7975     7981       +6     

Files with missing lines	Coverage Δ
lib/internal/test_runner/utils.js	61.27% <0.00%> (ø)

... and 27 files with indirect coverage changes

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