ci: hosted runner loses communication during DynamoDB net8.0 tests

Failure

The AWS DynamoDB provider tests (net8.0) job failed because its hosted runner lost communication with GitHub, before completing the test step or publishing its test artifacts.

• Run: https://github.com/dotnet/orleans/actions/runs/35398424261 (attempt 1)
• Job: https://github.com/dotnet/orleans/actions/runs/35398424261/job/105772493932
• Triggering PR: #11284
• Head: 5e9cafafd49d0654041889e315d5955bc2331fb5
• Runner: GitHub Actions 1006793696

The check annotation states:

The hosted runner lost communication with the server. Anything in your workflow that terminates the runner process, starves it for CPU/Memory, or blocks its network access can cause this error.

Available evidence

The job started at 2026-09-18T21:46:29Z and was marked failed at 22:41:30Z. Checkout and Start DynamoDB Local succeeded. The Test step started at 21:46:42Z, but its REST metadata still reports in_progress with no completion timestamp; cleanup and post-job steps remain pending.

gh run view --job 105772493932 --log-failed reports log not found. The run has DynamoDB net10.0 output/coverage artifacts, but no corresponding net8.0 artifact. No test assertion or specific test failure could be recovered from the available evidence.

Scope and investigation

The triggering changes concern durable Messaging/Journaling rather than the DynamoDB provider. This is currently classified as a hosted-runner failure with an unlocalized cause, not a confirmed DynamoDB product regression. The annotation alone does not distinguish process termination, CPU/memory starvation, or network loss.

Please investigate runner diagnostics/resource exhaustion and whether an active test or container operation prevented completion and artifact upload. Exact-message and DynamoDB runner/hang searches found no existing matching issue or recently merged fix. No workflow rerun or branch rebase was performed to replace the original failure evidence.