release-26.1: sql: increase page size when iterating over range descs

[yuzefovich]

Backport 1/1 commits from #161162 on behalf of @yuzefovich.

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Empirical testing has showed that if we increase the page size when iterating over the range descriptors for
crdb_internal.ranges_no_leases, we get a minor performance improvement. Thus, this commit bumps the page size from 128 to 10k. Going higher didn't show any meaningful difference because the overhead of the virtual table generation dominated. (Testing was done on a single region cluster, so perhaps it could benefit from still higher page size in multi-region clusters, but I don't think it would matter much in practice still.)

Informs: #160196.
Epic: None
Release note: None

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Release justification: low-risk improvement for large clusters.

[blathers-crl]

Thanks for opening a backport.

Before merging, please confirm that the change does not break backwards compatibility and otherwise complies with the backport policy. Include a brief release justification in the PR description explaining why the backport is appropriate. All backports must be reviewed by the TL for the owning area. While the stricter LTS policy does not yet apply, please exercise judgment and consider gating non-critical changes behind a disabled-by-default feature flag when appropriate.

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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

[cockroach-teamcity]

This change is 

[rafiss]

i don't have too much context on usages of RangeDescIteratorFactory/NewLazyIterator, but based on my read of this and the linked issue, this seems safe to backport.

[yuzefovich]

TFTR! We're simply increasing MaxSpanRequestKeys that is issued under the hood from 128 to 10k, and in my testing I have tried much larger values with no problem. For comparison, we use 100k value when we use limits for query scans (i.e. TableReader processor). Thus, the change should be effectively with no risk.