test_runner: print coverage and diagnostics with dot reporter

[madkate42]

Summary

When using the dot reporter with coverage thresholds, coverage failure messages and the coverage report were not displayed. The dot reporter only handled test:pass and test:fail events, ignoring test:diagnostic and test:coverage events.

This change adds handlers for these events, displaying:

• Diagnostic messages (including coverage threshold errors)
• The coverage report table

after the test dots complete.

Fixes: #60884
Refs: #52655

Test plan

• Added tests in test/parallel/test-runner-coverage-thresholds.js for dot reporter coverage failures
• Existing dot reporter tests continue to pass

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[pmarchini]

Could you please add a snapshot test too?

[madkate42]

great catch, thank you, added in this commit.
let me know if this could be improved!

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.77%. Comparing base (5a8f845) to head (3be8bad).
⚠️ Report is 1294 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/reporter/dot.js	71.42%	6 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #61891 +/- ##
==========================================
- Coverage 91.70% 89.77% -1.93% 
==========================================
Files 337 674 +337 Lines 140026 204906 +64880 Branches 21745 39385 +17640 ==========================================
+ Hits 128410 183964 +55554 - Misses 11393 13233 +1840 - Partials 223 7709 +7486 

Files with missing lines	Coverage Δ
lib/internal/test_runner/reporter/dot.js	90.00% <71.42%> (-10.00%)	⬇️

... and 458 files with indirect coverage changes

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[pmarchini]

The tests are failing and the failures seem to be related!

[SudhansuBandha]

The failures appear to be due to outdated snapshots.

Running:
python tools/test.py test-runner
updates the snapshot and all tests pass locally.

[JakobJingleheimer]

Duplicate of#61423