3.x: ShardAwarenessTest.correctShardInTracingTest flakes when tracing lacks querying locally event

[dkropachev]

Problem

ShardAwarenessTest.correctShardInTracingTest intermittently fails in the 3.x Scylla integration-test matrix because the query trace sometimes does not include any event whose description contains querying locally.

Observed on PR #943, head efe29bf2e24b357417d7134b6ac39c9659f9cd38, in Scylla ITs (LATEST, 8):

https://github.com/scylladb/java-driver/actions/runs/28683913680/job/85072817714

Failure:

java.lang.AssertionError: No 'querying locally' trace event was observed for the query expected [true] but found [false]
    at com.datastax.driver.core.ShardAwarenessTest.verifyCorrectShardSingleRow(ShardAwarenessTest.java:95)
    at com.datastax.driver.core.ShardAwarenessTest.correctShardInTracingTest(ShardAwarenessTest.java:115)

The same surefire result shows that this failed only on the first attempt and then passed on retry:

Run 1: ShardAwarenessTest.correctShardInTracingTest:115->verifyCorrectShardSingleRow:95 No 'querying locally' trace event was observed for the query expected [true] but found [false]
Run 2: PASS

A similar failure was also seen in an earlier PR #943 run, Scylla ITs (LTS-LATEST, 8), where the first invocation failed at ShardAwarenessTest.java:113 and the retry passed:

https://github.com/scylladb/java-driver/actions/runs/28670230744/job/85031593100

Notes

This does not look directly related to PR #943: that PR changes only Connection, RequestHandler, and RequestHandlerTest, while the failing test is ShardAwarenessTest.

There is a related merged fix in #931 for a different ShardAwarenessTest.correctShardInTracingTest failure on Scylla 2025.1. That fix made the anyLocal assertion real, so this missing-querying locally case now fails visibly, but I did not find an existing GitHub or Jira issue tracking this exact flaky symptom.

Expected

ShardAwarenessTest.correctShardInTracingTest should be deterministic in CI, or the test should wait/retry trace-event collection if the querying locally event can appear asynchronously.