v8: use primordials in startup_snapshot.js

[Ayoub-Mabrouk]

Replace native array methods (.push, .shift) with primordials (ArrayPrototypePush, ArrayPrototypeShift) in lib/internal/v8/startup_snapshot.js for consistency and security.

This improves protection against prototype pollution and aligns with the primordials pattern used throughout the codebase.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.53%. Comparing base (05d6b9b) to head (00bb902).
⚠️ Report is 79 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61199      +/-   ##
==========================================
- Coverage   88.53%   88.53%   -0.01%     
==========================================
  Files         703      703              
  Lines      208599   208618      +19     
  Branches    40229    40245      +16     
==========================================
+ Hits       184685   184690       +5     
- Misses      15939    15949      +10     
- Partials     7975     7979       +4     

Files with missing lines	Coverage Δ
lib/internal/v8/startup_snapshot.js	95.55% <100.00%> (+0.17%)	⬆️

... and 27 files with indirect coverage changes

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[avivkeller]

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