process: reject null bytes in chdir paths

[Archkon]

Validate directory strings before calling the native chdir binding to prevent paths from being truncated at embedded null bytes.

[nodejs-github-bot]

Review requested:

• @nodejs/startup

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.30%. Comparing base (c18fd90) to head (bebc86d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65068      +/-   ##
==========================================
- Coverage   90.31%   90.30%   -0.01%     
==========================================
  Files         759      759              
  Lines      247646   247646              
  Branches    46697    46692       -5     
==========================================
- Hits       223654   223643      -11     
- Misses      15463    15472       +9     
- Partials     8529     8531       +2     

Files with missing lines	Coverage Δ
...ernal/bootstrap/switches/does_own_process_state.js	95.13% <100.00%> (ø)

... and 32 files with indirect coverage changes

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