lib: return undefined for localStorage without file

[mcollina]

Make localStorage return undefined and emit a warning when
--localstorage-file is not provided. Mark the property as
non-enumerable to avoid breaking {...globalThis}.

Fixes: #60303

[codecov]

Codecov Report

❌ Patch coverage is 97.14286% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 88.34%. Comparing base (ce2ec3d) to head (c85a48b).
⚠️ Report is 47 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/process/pre_execution.js	94.73%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61333      +/-   ##
==========================================
- Coverage   88.54%   88.34%   -0.20%     
==========================================
  Files         704      704              
  Lines      208734   208762      +28     
  Branches    40271    40260      -11     
==========================================
- Hits       184823   184437     -386     
- Misses      15932    16373     +441     
+ Partials     7979     7952      -27     

Files with missing lines	Coverage Δ
lib/internal/webstorage.js	100.00% <100.00%> (ø)
lib/internal/process/pre_execution.js	98.43% <94.73%> (-0.10%)	⬇️

... and 61 files with indirect coverage changes

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[avivkeller]

Couldn't you keep this call the same, and do something like

ObjectDefineProperty(globalThis, 'localStorage', {
  enumerable: ...
});

Instead of re-writing the whole implementation?

[mcollina]

I'm sorry, but I don't understand what you are asking.