release-25.4: sql/importer: fix TestUniqueUUID timeout

[blathers-crl]

Backport 1/1 commits from #166309 on behalf of @mw5h.

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Summary

Disable elastic CPU control in TestUniqueUUID to prevent the test from
exceeding the 15m timeout. The test imports 50,000 rows across three
tables with UUID/random primary key defaults.

When the metamorphic constant import-row-count-validation selects
sync mode, each import synchronously waits for an INSPECT validation
job that scans the imported data. Combined with elastic CPU throttling
(which was recently enabled for import jobs), the cumulative scan time
across the three imports can exceed the test timeout.

This mirrors the fix applied to other import tests in bda9189.

Resolves: #166130
Epic: None

🤖 Generated with Claude Code

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Release justification:

[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.
• Other approved changes. These changes must be gated behind a disabled-by-default feature flag unless there is a strong justification not to. Reference the approved ENGREQ ticket in the PR body (e.g., "Fixes ENGREQ-123").

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 #166345 is compliant with backport policy

Confidence: high
Backward compatible: true
Explanation: The pull request is compliant with the backport policy for non-production changes. The changed file, 'pkg/sql/importer/import_stmt_test.go', is a test file, as indicated by the '_test.go' suffix. According to the CockroachDB backport policy, changes that only affect non-production code, such as tests or development tools, are exempt from the standard backport policy requirements. This includes not needing a critical bug justification or feature flag gating.

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

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[cockroach-teamcity]

This change is