module: do not split a portable compile cache by uid

[codebytere]

A portable compile cache is meant to be reused wherever the same module layout is found. One shape of that is a cache generated once, at build time, and shipped read-only with an application for whoever runs it. On platforms with uids the cache subdirectory is suffixed with the uid of the user who created it ($NODE_VERSION-$ARCH-$CACHE_DATA_VERSION_TAG-$UID), so such a cache is only ever found by that one user; the split exists so users sharing a writable directory do not trip over each other's file permissions.

This omits the uid suffix in portable mode only. A user who cannot write to the directory still reads it, and a failed write is only a cache miss (Persist already logs and skips a temp file it cannot create). Non-portable caches keep the suffix.

Docs updated for portable and NODE_COMPILE_CACHE_PORTABLE; test-compile-cache-api-portable now asserts the tag directory name.

Context: an Electron application generating its main-process cache at package time and shipping it beside its app.asar (module.enableCompileCache({ directory, portable: true }) at launch); measured on that app, the shipped cache roughly halves the launch bundle's load time, but with the uid in the tag it is only found by users whose uid matches the build machine's.

[nodejs-github-bot]

Review requested:

• @nodejs/loaders

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.31%. Comparing base (bc813a7) to head (2201240).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65293      +/-   ##
==========================================
- Coverage   90.32%   90.31%   -0.01%     
==========================================
  Files         751      751              
  Lines      249960   250031      +71     
  Branches    47204    47247      +43     
==========================================
+ Hits       225774   225823      +49     
- Misses      15564    15593      +29     
+ Partials     8622     8615       -7     

Files with missing lines	Coverage Δ
src/compile_cache.cc	79.21% <100.00%> (+0.12%)	⬆️

... and 36 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.