src: reuse cached strings in node_locks.cc

[agape1225]

CreatePerIsolateProperties() in src/node_locks.cc created new "shared" and "exclusive" V8 strings via FIXED_ONE_BYTE_STRING() on every isolate, even though these strings are already cached on IsolateData as shared_string() / exclusive_string() (defined via PER_ISOLATE_STRING_PROPERTIES in src/env_properties.h) and are already reused this way elsewhere in the same file (CreateLockInfoObject()).

This replaces the two ad-hoc FIXED_ONE_BYTE_STRING(isolate, "shared"/"exclusive") calls with the existing cached accessors for consistency with the rest of the file and to avoid creating duplicate string instances.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.32%. Comparing base (ee64033) to head (2bc2f72).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65081      +/-   ##
==========================================
+ Coverage   90.29%   90.32%   +0.02%     
==========================================
  Files         759      759              
  Lines      247754   248258     +504     
  Branches    46721    46848     +127     
==========================================
+ Hits       223708   224230     +522     
+ Misses      15521    15459      -62     
- Partials     8525     8569      +44     

Files with missing lines	Coverage Δ
src/node_locks.cc	72.67% <100.00%> (ø)

... and 36 files with indirect coverage changes

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[daeyeon]

Please add the Signed-off-by trailer to your commit message to pass the linter check.

[daeyeon]

Thanks for the contribution. I missed this during my initial review. Duplicate of #65039.