Split up monster test_window_partial_constant_and_set_monotonicity into smaller functions

[alamb]

Which issue does this PR close?

• Another try at Refactor: Split test_window_partial_constant_and_set_monotonicity from enforce_sorting #17903

Rationale for this change

I am working on the arrow 57 upgrade and I found I had to update the output of
many tests. I broke some of the changes out into their own PR for easier review

This one in particular breaks the 1200+ line test test_window_partial_constant_and_set_monotonicity, including 47 test cases in into individual tests so they are easier to update. Without this change, updating all 47 tests requires running the following commands in a loop:

cargo test --profile=ci --test core_integration -- enforce_sorting # fails on the first diff
cargo insta review # (and then hit a to accept the changes for the first diff)

What changes are included in this PR?

1. Move the code to a new file
2. Move testing code into functions rather than a macro
3. Rewrite all test cases (used copilot)

Are these changes tested?

Are there any user-facing changes?