opt: fix error due to estimated row count must be non-zero

[rytaft]

This commit fixes an error in the statistics code that was caused by integer overflow when calculating the distinct count.

Fixes #85499

Release note (bug fix): Fixed a rare internal error that could occur during planning when a predicate included values close to the maximum or minimum int64 value. The error, "estimated row count must be non-zero", has now been fixed.

[cockroach-teamcity]

This change is 

[craig[bot]]

Build succeeded:

• Bazel Essential CI (Cockroach)

[blathers-crl[bot]]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from 24caf3750b126853a3c57e521f0a35492c78e506 to blathers/backport-release-22.1-88494: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 22.1.x failed. See errors above.

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