Remove houdini-dependent test from compat2021 set

[dholbert]

The WPT test transform-interpolation-computed-value.html is entirely dependent on a CSS Houdini API, in its testing of CSS Transform interpolation. The top of the test also references (only) Houdini as the spec being tested:

<link rel="help" href="https://drafts.css-houdini.org/css-typed-om/#transformvalue-objects">

At this point, the CSS Houdini APIs are only implemented in Chromium. So this test only passes in Chromium, due to its dependence on these APIs (specifically computedStyleMap).

It's not clear that Houdini itself is a source of interop issues at this point, so it doesn't make a lot of sense to include houdini-dependent tests in the compat2021 test set. Therefore, I propose we remove this test from the test set.

[dholbert]

For reference, here's the wpt.fyi link for this test (failing all 82 subtests on Firefox and Safari):
https://staging.wpt.fyi/results/css/css-transforms/animation/transform-interpolation-computed-value.html

Here's the GitHub link to the test itself (showing its computedStyleMap usage and its <link rel="help"> tag pointing at Houdini as the thing-being-tested):
https://github.com/web-platform-tests/wpt/blob/master/css/css-transforms/animation/transform-interpolation-computed-value.html

Note: this test wasn't originally 100%-houdini-dependent -- it originally had a piece that queried the interpolated value using a different API (commitStyles), as noted in its original commit message at web-platform-tests/wpt@2011547 ("Two variants... computedStyleMap().get().toString() which is supported by chrome.... [and] commitStyles, which in implemented in both firefox and chrome")

But that commitStyles piece of the test was split out into a separate file in web-platform-tests/wpt@cf4e4b2 . The split-out test is here:
https://wpt.fyi/results/css/css-transforms/animation/transform-interpolation-inline-value.html
(and there could be a case for it to be added to the test suite, though it's a bit late in 2021 to be adding tests)

With that piece split out, the remaining transform-interpolation-computed-value.html test is entirely relying on the Houdini computedStyleMap API in all of its subtests, and therefore doesn't make a ton of sense as a transform-interop benchmark, given the current implementation status of Houdini, and the fact that Houdini and transforms are entirely independent features.

[dholbert]

[CC'ing @foolip and @stephenmcgruer ]

[foolip]

The state of the test at the time it was included in this list was the original version of it:
https://github.com/web-platform-tests/wpt/blob/201154711dd0e06c817880c7c9396a0d7188a8f5/css/css-transforms/animation/transform-interpolation-computed-value.html

That original version used computedStyleMap() from CSS Typed OM, and I agree it shouldn't have been included in Compat 2021.

If transform-interpolation-inline-value.html tests the same thing but avoids CSS Typed OM it would probably be a good idea to include, but only after a discussion. I'll bring it up in web-platform-tests/interop#2.

[foolip]

I've sent web-platform-tests/wpt-metadata#2217 to make the matching change for the interop-2021 label. We will need to rewrite the score computation to use the labels instead of lists of tests, but for now I'll keep them manually in sync. (Interop 2022 will be just labels, so the problem has to be fixed soon.)