Move more rewriting to SafeRewrite

[systay]

Description

More of the same - we want to only change the AST after visiting the children of a struct, and not before.
If we allow changing the struct we are standing on, and then visiting it, we would need to update the generated code to allow for this. The current code allows this to happen but the behaviour is not tested and probably buggy. In all places I could find, we were only doing this replacement on leaf nodes, which probably was our saving grace.

This PR changes more places to use SafeRewrite, which through the API only allows for changing the AST after visiting the children.

Related Issue(s)

Part of #12123

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests were added or are not required
• Documentation was added or is not required

[vitess-bot]

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