Fix anchor-scroll-position-try-004.html to increase its 1000px sizes to be something larger

[dholbert]

Test List

https://wpt.fyi/results/css/css-anchor-position/anchor-scroll-position-try-004.html

Rationale

This test (runnable here on wpt.live) has a flaky dependency on being run in a browser that's less than 1100px wide. (It has a 100px wide element with margin-left:1000px and it assumes that this is sufficient to push the element off the right side of the viewport.)

If you view it in any browser in a viewport that's 1100px wide or wider, the final subtest fails (with the actual value being 100px more than the expectation, because the element unexpectedly did not overflow and did not need to jump to the fallback position that the test is trying to nudge it to).

As it turns out, Firefox's wpt.fyi infrastructure runs testharness.js-based tests (like this one) in a browser that is just a little larger than 1100px wide, so Firefox is reported as failing this test due to its window-size-dependency.

I propose that we increase the 1000px "big sizes" in the test's CSS to something larger -- say, 4000px -- to be much further outside the realm of reasonable-test-harness-browser-sizes.

[dholbert]

(Apologies for the sorta last minute test-change request; we overlooked this issue until now. Fortunately it's pretty trivial and the "failing" behavior is interoperable, and the only Firefox-specific thing is the window-size that we happen to use on wpt.fyi test runs for testharness.js tests.)

PR to make the test more robust (s/1000px/4000px/) in web-platform-tests/wpt#56798

@nt1m @bfgeek does this seem OK to you?

[bfgeek]

yup thats fine.

[dholbert]

@gsnedders from Apple said it seems fine over on the PR, so I think we're good to proceed. Thanks!

[gsnedders]

Sorry, meant to comment here too, and then got side-tracked!