release-22.2: constraint: perform cancel checking when combining constraints

[blathers-crl]

Backport 1/1 commits from #111979 on behalf of @msirek.

/cc @cockroachdb/release

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Previously, the combining of constraint spans when one constraint is a
suffix of the other could take a long time and cause the
statement_timeout session setting to not be honored when each
constraint has hundreds or thousands of spans.

The issue is that constraint.Combine has double nested loops to
consider every combination of one span from one constraint with one span
of the other constraint. The building of possibly millions of spans
may take excessive CPU time and allocate excessive amounts of memory.

The fix is to maintain a counter in constraint.Combine and call the
query cancel check function every 16 iterations. The cancel check
function itself will check for query timeout every 1024 iterations, so
effectively every 16K iterations constraint.Combine will perform
cancel checking and abort the query if the timeout has been reached.

Epic: none
Fixes: #111862

Release note (bug fix): This patch fixes an issue where the optimizer
fails to honor the statement_timeout session setting when generating
constrained index scans for queries with large IN lists or = ANY
predicates on multiple index key columns, which may lead to an out
of memory condition on the node.

---

Release justification: Critical fix which allows the statement_timeout setting to be honored and avoid OOMs on queries with many constants in = ANY or IN list predicates.

[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 

[yuzefovich]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @cucaroach, @DrewKimball, and @msirek)