worker: parse NODE_OPTIONS when env option is not provided

[semimikoh]

When env option is not explicitly provided to new Worker(),
runtime changes to process.env.NODE_OPTIONS (e.g. adding --import)
are not picked up by the worker thread.

This happens because in node_worker.cc, the NODE_OPTIONS parsing
block is gated behind args[1]->IsObject() || args[2]->IsArray().
When env is not provided, args[1] is null (cloned from
process.env), so the condition is false and NODE_OPTIONS parsing
is skipped entirely.

This fix adds args[1]->IsNull() to the condition so that
NODE_OPTIONS is also parsed when the env is inherited (cloned)
from the parent process.

Fixes: #62301

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.66%. Comparing base (4d2d6de) to head (9f345a9).
⚠️ Report is 18 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main   #62306    +/-   ##
========================================
  Coverage   89.66%   89.66%            
========================================
  Files         676      676            
  Lines      206575   206693   +118     
  Branches    39555    39583    +28     
========================================
+ Hits       185225   185339   +114     
+ Misses      13501    13495     -6     
- Partials     7849     7859    +10     

Files with missing lines	Coverage Δ
src/node_worker.cc	81.31% <100.00%> (-0.10%)	⬇️

... and 45 files with indirect coverage changes

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[mertcanaltin]

Thank you, could you add a test for this?

[semimikoh]

@mertcanaltin

Added a test in 9f345a9. It verifies that NODE_OPTIONS set at runtime are picked up by a worker when the env option is not provided.