release-24.3: ccl/multiregionccl: deflake TestMultiRegionDataDriven_global_tables

[blathers-crl]

Backport 1/1 commits from #166247 on behalf of @cockroach-teamcity.

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The test was flaky because the cluster setting
kv.closed_timestamp.lead_for_global_reads_auto_tune.enabled uses a
metamorphic constant that can randomly enable auto-tuning during tests.
When enabled on a localhost test cluster (near-zero inter-node latency),
auto-tuning selects a lower-latency policy bucket, reducing the closed
timestamp lead time. This reduced lead time provides insufficient buffer
for follower reads to be served consistently, causing the closed timestamp
to be too low (~27ms) when the test asserts that a GLOBAL table read is
served via follower read.

Explicitly disable auto-tuning in the test's cluster setup to ensure a
stable closed timestamp lead time.

Resolves: #165405
Resolves: #165266

Release note: None

Generated by Claude Code Auto-Solver
Co-Authored-By: Claude noreply@anthropic.com

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 pkg/ccl/multiregionccl/datadriven_test.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

This PR was auto-generated by issue-autosolve using Claude Code.
Please review carefully before approving.

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Release justification:

[trunk-io]

Merging to release-24.3 in this repository is managed by Trunk.

• To merge this pull request, check the box to the left or comment /trunk merge below.

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that it falls into one of the following categories (select one):

• Non-production code changes OR fixes for serious issues. Non-production includes test-only changes, build system changes, etc. Serious issues are defined in the policy as correctness, stability, or security issues, data corruption/loss, significant performance regressions, breaking working and widely used functionality, or an inability to detect and debug production issues.
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Add a brief release justification to the PR description explaining your selection.

Also, confirm that the change does not break backward compatibility and complies with all aspects of the backport policy.

All backports must be reviewed by the TL and EM for the owning area.

[blathers-crl]

✅ PR #166248 is compliant with backport policy

Confidence: high
Backward compatible: true
Explanation: The pull request is compliant with the backport policy specifically under the non-production assessment exception. The changes are confined to a test file (pkg/ccl/multiregionccl/datadriven_test.go) which matches the patterns for non-production files as defined by the backport policy. Given this, the pull request is exempt from the requirements of fixing a critical bug or needing to be gated behind a feature flag. Additionally, the pull request aims to deflake a test, focusing on the stability in the test environment which is a common and accepted practice in backports.

❌ ENGREQ Check Failed: Please check one of the backport category checkboxes.

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[cockroach-teamcity]

This change is