src: improve node:os userInfo performance

[anonrig]

Improve node:os userInfo performance by reducing the cost of creating a v8::Object.

[codecov]

Codecov Report

Attention: Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.

Project coverage is 88.39%. Comparing base (bdc2662) to head (55614e5).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/node_os.cc	94.11%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #55719      +/-   ##
==========================================
+ Coverage   88.38%   88.39%   +0.01%     
==========================================
  Files         654      654              
  Lines      187575   187651      +76     
  Branches    36096    36110      +14     
==========================================
+ Hits       165795   165883      +88     
+ Misses      15004    14998       -6     
+ Partials     6776     6770       -6     

Files with missing lines	Coverage Δ
lib/os.js	97.31% <ø> (-0.04%)	⬇️
src/node_os.cc	82.37% <94.11%> (+0.06%)	⬆️

... and 17 files with indirect coverage changes