PanicHandlerTest::test_03_heap_handling - AssertionError: failed to dump end line

[jiridanek]

https://github.com/skupperproject/skupper-router/actions/runs/7260840822/job/19780826786?pr=1314#step:34:1436

This seems to be a rare flake.

[jiridanek]

https://github.com/skupperproject/skupper-router/actions/runs/7355985652/job/20025426535?pr=1281#step:34:1902

[kgiusti]

What I think is happening here is that two threads are hitting SEGFAULT at the same time. Both attempt to write to stdout and that produces scrambled output.

If that's the case we probably want to limit the dump to the first thread that hits it. Maybe use an atomic flag that is set by the first thread. Any following threads would not produce the backtrace if the flag is set.