test: unflake debugger and REPL tests

[mcollina]

Refs: https://github.com/nodejs/node/actions/runs/30080039199/job/89439279468?pr=64339

The macOS job exposed two independent races:

• The debugger could start its REPL before a delayed Debugger.paused
  notification rendered the initial break. The job had already printed the
  debug> prompt when test-debugger-extract-function-name timed out waiting
  for the break message. Create the initial-break deferred before resuming the
  target, await the completed render, and settle the deferred if the client
  closes without pausing.
• test-repl-user-error-handler could receive an inspector
  Promise was collected evaluation error before the user error it intended to
  assert. Give this focused handleError test a synchronous VM evaluator,
  submit the throwing and follow-up expressions separately, and await clean
  REPL teardown.

The debugger mock test now delays both the pause notification and its render,
which reproduces the prompt-ordering race deterministically without the fix.
The REPL failure reproduced locally on macOS after rebuilding current main.

[avivkeller]

LGTM, but note that the flake won't be entirely resolved until https://chromium-review.googlesource.com/c/v8/v8/+/8123081 lands¹

Footnotes

1. Running async, as you've done, makes this far more unlikely, but there's still a (albeit <0.1% chance, per my testing) chance of it catching itself, if GC occurs at a poor time ↩

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/75103/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.12%. Comparing base (c558c8e) to head (58ed4da).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64718      +/-   ##
==========================================
- Coverage   90.15%   90.12%   -0.03%     
==========================================
  Files         741      743       +2     
  Lines      242251   242313      +62     
  Branches    45624    45634      +10     
==========================================
+ Hits       218391   218395       +4     
- Misses      15351    15424      +73     
+ Partials     8509     8494      -15     

Files with missing lines	Coverage Δ
lib/internal/debugger/inspect_repl.js	92.07% <100.00%> (+0.76%)	⬆️

... and 58 files with indirect coverage changes

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