[Feature] Preserve core dumps and matching test binaries in CI

[zjw1111]

Search before asking

• I searched in the issues and found nothing similar.

Motivation

When a test crashes in the Build and Test workflow, build_support/run-test.sh prints a backtrace if it can find a core dump, but then deletes the core file together with the test work directory. The workflow also does not enable core dump generation or upload debugging artifacts.

As a result, crashes reported as (core dumped) cannot be investigated offline after the CI job finishes. Preserving the dump and its matching executable would make intermittent native crashes diagnosable.

Solution

• Enable unlimited core dumps and set kernel.core_pattern=core.%e.%p in the same shell that runs ci/scripts/build_paimon.sh.
• Keep printing all-thread backtraces in CI.
• Move discovered core files to the persistent test debug directory instead of deleting them.
• Preserve the exact matching test executable alongside each core dump.
• Upload the debug directory as a matrix-specific artifact when a build-and-test job fails, with a short retention period.

Anything else?

The implementation is available in #312.

Are you willing to submit a PR?

• I am willing to submit a PR!