xform: make FoldDivOne an essential normalization

[msirek]

Fixes #86790

This fixes sqlsmith errors caused by differences in the number of displayed digits right of the decimal place for expression / 1 by making the folding of this expression essential.

Release note: None

[cockroach-teamcity]

This change is 

[craig[bot]]

Build succeeded:

• Bazel Essential CI (Cockroach)

[mgartner]

Which backport releases do you think are appropriate?

I think 22.2 would be good.

[msirek]

blathers backport release-22.2

[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 956948ed0ba3a76bcfbd607d55985924d2b9233e to blathers/backport-release-22.2-88485: 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 release-22.2 failed. See errors above.

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