chore: update sqllogictest priority list with latest timing summary (8s --> 6s)

[alamb]

Which issue does this PR close?

• Follow-up to Add tests for sqllogictest prioritization #20656.

Rationale for this change

Make running sqllogictests faster by improving scheduling / parallelism

The sqllogictest runner runs test files in parallel but each file
sequentially, so it prioritizes known long-running files to run first to
minimize total wall-clock time. This list was last set in #20656.

The relative timings have since shifted. Running with the
--timing-summary flag now reports a different ordering of the longest
files, with nested_loop_join_spill.slt having become the longest by a
fair margin:

$ cargo test --profile=ci --test sqllogictests -- --timing-summary
Per-file elapsed summary (deterministic):
1. 5.437s nested_loop_join_spill.slt
2. 3.471s push_down_filter_regression.slt
3. 3.458s aggregate.slt
4. 3.065s joins.slt
5. 2.852s aggregate_skip_partial.slt
6. 2.832s imdb.slt
7. 2.453s window.slt
8. 1.831s group_by.slt
9. 1.282s clickbench.slt
10. 1.055s datetime/timestamps.slt
11. 0.994s array/array_has.slt
12. 0.840s cte.slt
13. 0.748s sort_pushdown.slt
14. 0.714s push_down_filter_parquet.slt
15. 0.668s projection_pushdown.slt

What changes are included in this PR?

• Update TEST_PRIORITY_ENTRIES to match the latest --timing-summary ordering
• Update the example output in the accompanying doc comment.

Are these changes tested?

There are some existing unit tests and I verified timings manually

cargo test --profile=ci --test sqllogictests

Main

Running with 16 test threads (available parallelism: 16)
Completed 475 test files in 8 seconds

This Branch

andrewlamb@Andrews-MacBook-Pro-3:~/Software/datafusion3$ cargo test --profile=ci --test sqllogictests
Finished `ci` profile [unoptimized] target(s) in 0.53s
Running bin/sqllogictests.rs (target/ci/deps/sqllogictests-0a94fbc565e8c132)
Running with 16 test threads (available parallelism: 16)
Completed 475 test files in 6 seconds

Are there any user-facing changes?

No.

[2010YOUY01]

LGTM, thank you!

[alamb]

Thank you for the review @2010YOUY01