lib: format default abort reason stack eagerly

[kuldeeepy]

When abort() is called without a reason, the default AbortError keeps its stack unformatted, and V8 then holds on to the caller's frames (receivers and closures). A retained signal can keep the cancelled job and its buffers alive.

This reads the stack once when the default reason is created, like checkError() in streams does. It covers both controller.abort() and AbortSignal.abort(). AbortSignal.timeout() doesn't have this problem because its reason is created in a timer callback. Reasons passed by the caller aren't touched, and a throwing Error.prepareStackTrace doesn't make abort() throw.

abort() without a reason gets slower (static abort benchmark: about 569k to 340k ops/s). Passing a reason isn't affected.

Fixes: #66192

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Disclosure: prepared with assistance from Claude Code. I reproduced the leak, checked the fix against the source, and ran the new and existing abort tests on a local build.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.28%. Comparing base (e7d8ab5) to head (b03f41d).
⚠️ Report is 20 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #66265      +/-   ##
==========================================
- Coverage   90.30%   90.28%   -0.02%     
==========================================
  Files         789      789              
  Lines      272880   272893      +13     
  Branches    52110    52111       +1     
==========================================
- Hits       246418   246390      -28     
- Misses      16912    16963      +51     
+ Partials     9550     9540      -10     

Files with missing lines	Coverage Δ
lib/internal/abort_controller.js	95.49% <100.00%> (+0.08%)	⬆️

... and 26 files with indirect coverage changes

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