test: allow one more shutdown reason

[koivunej]

Recent evidence: https://neon-github-public-dev.s3.amazonaws.com/reports/pr-7726/9061173606/index.html#/testresult/d44e6075034a8925

Previous attempt: #7622

[koivunej]

There's actually two. Unsure how many of these PRs does it make sense to make, we should just fix the error types and not warn if something fails because of shutdown.

[github-actions]

3060 tests run: 2928 passed, 0 failed, 132 skipped (full report)

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Code coverage* (full report)

• functions: 31.4% (6331 of 20161 functions)
• lines: 47.3% (47763 of 100969 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
7c878d2 at 2024-05-13T13:21:52.504Z :recycle:}