1. 1. Summary

• When all core dumps from a parent task are "boring" (routine SIGABRT teardown), the `core_analysis` task now exits successfully instead of system-failing with `RuntimeError("Artifacts were not found")`
• `download_core_dumps()` in `extractor.py` returns `True` early when all cores were filtered as boring
• `core_analyzer.py` adds a defense-in-depth check: if no `.core`/`.mdmp` files exist after download, it writes a minimal report and exits cleanly
• The `s3.put` for `mongo-coreanalysis.tgz` is now marked `optional: True` as a safety net

Fixes [BF-42164](https://jira.mongodb.org/browse/BF-42164). This addresses a recurring issue with *22+ historical BFs* where `system-failed: core_analysis_*` tasks fail because all cores are boring.

1. 1. Test plan

• [ ] Verify existing `core_analysis` unit tests pass
• [ ] Check the waterfall after merge for `core_analysis` tasks on TSAN variants — they should no longer system-fail when all cores are boring
• [ ] Manually activate a `core_analysis` task with only boring cores and confirm it succeeds