sql: Enable cast elimination by default

[ggevay]

Motivation

Add testing coverage after #35084; to prepare for rollout.

Description

Turn on enable_cast_elimination by default. Rewrite SLTs (eliminating varchar_to_text and reordering some filter clauses; use git diff --word-diff --word-diff-regex=. for a readable diff).

Verification

Existing tests failed; rewritten to get things green. Adding nightly and release verification runs, as well.

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[mgree]

LGTM! (Will have @ggevay get eyes on this as well.)

[ggevay]

Thanks for the rewrites, looks good!

Turned on also in LD for the next version.