release-22.2: opt: allow lookup joins to preserve index ordering with DESC columns

[blathers-crl]

Backport 1/1 commits from #93673 on behalf of @DrewKimball.

/cc @cockroachdb/release

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This patch fixes an oversight of #84689 that prevented lookup joins from maintaining the index ordering for each lookup if the index ordering contained descending columns. The execution logic will respect descending index columns as-is, so only the optimizer code needed to be changed. This will allow plans with lookup joins to avoid sorts in more cases.

Fixes #88319

Release note (performance improvement): The optimizer can now avoid planning a sort in more cases with joins that perform lookups into an index with one or more columns sorted in descending order. This can significantly decrease the number of rows that have to be scanned in order to satisfy a LIMIT clause.

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Release justification:

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Patches should only be created for serious issues or test-only changes.
• Patches should not break backwards-compatibility.
• Patches should change as little code as possible.
• Patches should not change on-disk formats or node communication protocols.
• Patches should not add new functionality.
• Patches must not add, edit, or otherwise modify cluster versions; or add version gates.

If some of the basic criteria cannot be satisfied, ensure that the exceptional criteria are satisfied within.

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters.
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.

Add a brief release justification to the body of your PR to justify this backport.

Some other things to consider:

• What did we do to ensure that a user that doesn’t know & care about this backport, has no idea that it happened?
• Will this work in a cluster of mixed patch versions? Did we test that?
• If a user upgrades a patch version, uses this feature, and then downgrades, what happens?

[cockroach-teamcity]

This change is 

[DrewKimball]

Letting this bake for a week or so.

[yuzefovich]

Reviewed 7 of 7 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @DrewKimball, @mgartner, and @msirek)

[DrewKimball]

TFTR!