lib: fix phantom EACCES on spawn in some environments

[watilde]

On some Linux environments (e.g. WSL), execvp may return EACCES instead of ENOENT when a command is not found in PATH, if it encounters permission errors during the search. This change adds a check to verify if the file actually exists in PATH when EACCES is received for a command without path separators. If not found, the error is normalized to ENOENT.

refs: https://gist.github.com/watilde/db38ff0335834a32a6eebaa6b3373b8b

Once this is merged, I plan to add a CI setup for the WSL Distribution, which I believe will have a fair amount of users.

[codecov]

Codecov Report

❌ Patch coverage is 94.28571% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.53%. Comparing base (0457bfe) to head (1af02a1).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/child_process.js	94.28%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61253      +/-   ##
==========================================
- Coverage   88.53%   88.53%   -0.01%     
==========================================
  Files         704      704              
  Lines      208736   208775      +39     
  Branches    40274    40288      +14     
==========================================
+ Hits       184810   184836      +26     
- Misses      15944    15957      +13     
  Partials     7982     7982              

Files with missing lines	Coverage Δ
lib/internal/child_process.js	95.04% <94.28%> (-0.04%)	⬇️

... and 29 files with indirect coverage changes

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