release-25.4: concurrency: update wait queues in AddDiscoveredLock

[stevendanna]

Backport 1/1 commits from #147065 on behalf of @stevendanna.

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Concurrent readers in the face of a concurrent, retrying writer can result in a situation where AddDiscoveredLock moves the timestamp of a held intent past the read timestamp a waiting reader. The reader should be unblocked in this case but previously wasn't, resulting in a lock table verification assertion failure in the form of:

error: non locking reader ... does not conflict with lock holder

This is my best theory for what is happening in #146749 based on increased logging. It is difficult to be certain given the required ordering of events is hard to observe with locking.

See the comment in the test for a more complete timeline that can lead to the bug.

Fixes #146749

Release note: None

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Release justification: Bug fix for node crashing bug.

[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.

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[cockroach-teamcity]

This change is 

[blathers-crl]

✅ PR #161505 is compliant with backport policy

Confidence: high
Critical bug criteria met: [Stability or security issues]
Backward compatible: true
Explanation: The pull request is compliant with the backport policy. It contains a 'Release justification: Bug fix for node crashing bug' line in the body, which directly addresses a critical stability issue identified by a verification assertion failure potentially leading to node crashes. These criteria justify the need for backporting as part of the critical bug criteria.

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