release-25.2: roachtest: link on large pool

[rickystewart]

Backport 1/1 commits from #157927 on behalf of @rickystewart.

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Release note: none
Epic: none

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Release justification: Non-production code changes

[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. Includes test-only changes, build system changes, etc.
• Fixes for serious issues. 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.

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 #157935 is compliant with backport policy

Confidence: high
Backward compatible: true
Explanation: The PR changes a file classified as non-production under development tools ('pkg/cmd/roachtest/'). According to the policy, changes that only affect non-production code such as tests, development tools, or build configurations do not require a critical bug justification or a feature flag. These types of changes are exempt from the standard backport requirements.

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is