implement array_shuffle

[gushul]

Implemented array_shuffle function for postgres under #4153

[weiznich]

Seems like the CI job fails as we use a Postgres version for our tests that does not support array_shuffle yet. I will look at how to solve that next week.

[kw217]

Obviously this test will fail in just under 1% of runs, when the shuffle happens to do nothing. I'm a bit uncomfortable about this - one test like this might be fine, but if we set a precedent and we had many tests like this our suite will become flaky and "just rerun the suite" will become a common approach rather than digging into the problem.
@weiznich please let me know if you think I'm being overcautious.
A simple alternative would be

  println!("{:?}", shuffled); // e.g., `[3, 2, 5, 1, 4]`

[Mingun]

You can set bits corresponding to numbers in vec and check that the result is 31.

[kw217]

Yep, or sort the result in Rust and compare with the sorted array.

[weiznich]

I had another look at this and I think the best way forward for now is to mark this test as no_run doc-test as we cannot expect that all contributors have postgres 16 installed locally. That would mean we compile but don't run the test, which is fine for this case. We also should have a comment there saying that the no_run setting is there because the test requires postgres 16.

[weiznich]

I've just changed the test to no_run, otherwise this looks good to me. Thanks for working on this 👍