[ISSUE #10822] Classify BrokerShutdownTest as a medium Bazel test

[fuyou001]

Which Issue(s) This PR Fixes

• Fixes [Bug] BrokerShutdownTest times out under Bazel small test classification #10822

Brief Description

Classify BrokerShutdownTest as a Bazel medium test so that its generated test rule receives a timeout appropriate for its workload.

BrokerShutdownTest performs four complete broker initialize, start, and shutdown cycles. Broker shutdown serially stops Netty event executors, message-store services, POP services, timer services, and other background resources. In the observed GitHub Actions failure, the target inherited the default small classification and timed out after 61.6 seconds while the fourth shutdown was progressing normally.

The same timeout was also observed on unrelated pull requests, so this is an existing test-size classification issue rather than a regression from the triggering change.

Observed failure: https://github.com/apache/rocketmq/actions/runs/31065433437/job/92502049511

This change only adjusts the Bazel timeout classification. Production code and test behavior are unchanged.

How Did You Test This Change?

• Ran git diff --check successfully.
• Verified that GenTestRules maps entries in medium_tests to size = "medium".
• Confirmed that the PR contains only the three-line broker/BUILD.bazel classification change.
• Local Bazel execution was not run because Bazel is not installed in the local environment; GitHub Actions will provide the end-to-end Bazel validation.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.26%. Comparing base (2daf0e2) to head (9c74fe9).

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10821      +/-   ##
=============================================
- Coverage      48.32%   48.26%   -0.07%     
+ Complexity     13516    13503      -13     
=============================================
  Files           1380     1380              
  Lines         101138   101138              
  Branches       13120    13120              
=============================================
- Hits           48876    48815      -61     
- Misses         46298    46335      +37     
- Partials        5964     5988      +24     

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[RockteMQ-AI]

Fixes the flaky BrokerShutdownTest timeout by correctly classifying it as a medium Bazel test. The test runs four full broker lifecycle cycles which legitimately exceeds the small (60s) timeout — moving to medium (300s) is the right call.

LGTM. Clean, minimal change with clear justification.

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Automated review by github-manager-bot

[RockteMQ-AI]

Summary

Defensive fix with proper validation and test coverage. LGTM.

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Automated review by github-manager-bot