Dump forked-process threads on log-injection smoke-test timeout

[bm1549]

What Does This Do

On the "check raw file injection" smoke-test 30s timeout, jstack the forked process and attach the dump to the failure — so the OpenJ9/Semeru hang can be diagnosed instead of a bare "Condition not satisfied". Also distinguishes an early process exit from a genuine hang. Reinstates (a much smaller version of) the diagnostic from #11400, removed in #11548.

Motivation

The test times out with traceCount=0 and the forked process never exiting — a startup hang, only on IBM Semeru / OpenJ9. #11509 fixed the earlier DDTraceId clinit deadlock; this resurfaced after Semeru jobs began running on master/MQ (#11788, #11832). It couldn't be reproduced by brute force (~12k startups), so capture a thread dump when it next hangs on master/MQ.

Additional Notes

Runs only on the failure path. Follow-up (separate PR): @Flaky's isIbm8() reads java.vm.vendor="Eclipse OpenJ9", so it never matches Semeru — should be isJ9().

Jira ticket: N/A

🤖 Generated with Claude Code

[datadog-official]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 57.03% (-0.02%)

_{This comment will be updated automatically if new data arrives.
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[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.76 s	14.72 s	[-0.5%; +1.0%] (no difference)
startup:insecure-bank:tracing:Agent	13.53 s	13.73 s	[-2.4%; -0.5%] (maybe better)
startup:petclinic:appsec:Agent	16.79 s	16.63 s	[-0.0%; +1.9%] (no difference)
startup:petclinic:iast:Agent	16.84 s	16.93 s	[-1.2%; +0.2%] (no difference)
startup:petclinic:profiling:Agent	16.75 s	16.85 s	[-1.9%; +0.7%] (no difference)
startup:petclinic:sca:Agent	16.95 s	16.80 s	[+0.0%; +1.8%] (maybe worse)
startup:petclinic:tracing:Agent	16.06 s	15.74 s	[-2.4%; +6.5%] (no difference)

Commit: 5f34d403 · CI Pipeline · Benchmarking Platform UI

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