Reduce the amount of text in WPT inline-with-offset-from-containing-block.html (to reduce the amount of fuzziness needed)

[dholbert]

Test List

https://wpt.fyi/results/css/css-view-transitions/inline-with-offset-from-containing-block.html

Rationale

This test has always had an extremely permissive fuzzy annotation -- it was added with up to 1400 pixels allowed to be completely different and that was later increased to 1633 pixels to get it passing in Safari.

This fuzziness is due to text getting rasterized at a low resolution and then getting scaled. That in-and-of-itself might be worth avoiding, but it seems to not be what this test is trying to test, given this history of fuzzy annotation.

Firefox currently is flagged as failing the test because we have more fuzzy pixels than the currently-annotated tolerance, but I think fundamentally we behave the same as Safari does (and as Chrome did when the test was checked in).

But rather than increase the pixel-mismatch-count to get Firefox passing (which would make the test even more permissive of arbitrary breakage), let's reduce the amount of text in the testcase so that we can lower the number of fuzzy pixels that we need to allow. I propose we change "Some text" to "A B", and then reduce the fuzzy annotation to match observed needed levels.

[dholbert]

As suggested by @gsnedders , I adjusted the test to use the Ahem font as well, which further reduces the fuzzy tolerance needed.

@noamr, you helped with another similar test-change-proposal earlier today (thanks!) - would you mind signing off on this one as well? (And @gsnedders , perhaps you could sign off on behalf of WebKit?)

[dholbert]

Approved by @nt1m and @noamr in the PR (thanks!) --> Merged.