Tweak aoc slts to use more EXPLAIN options

[ggevay]

Adds more options to the EXPLAINs in the Advent of Code slts.

Motivation

My main motivation for this is that I'd like to see the details of join plan changes in #31281

Also, it's better to be uniform across our slts, and tpch as well as ldbc slts already use these options that I'm adding in this PR for aoc.

Tips for reviewer

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
• If this PR will require changes to cloud orchestration or tests, there is a companion cloud PR to account for those changes that is tagged with the release-blocker label (example).
• If this PR includes major user-facing behavior changes, I have pinged the relevant PM to schedule a changelog post.

[mgree]

LGTM!