Remove workaround for csstree

[asamuzaK]

w3c/webref#1647 is fixed.

[domenic]

Nice.

[asamuzaK]

css-syntax-patches-for-csstree had a bug.
csstools/postcss-plugins#1760

When releasing a new cssstyle, make sure to update it again.

[domenic]

Can you send an update PR with a test that would catch the bug? (Maybe such a test already exists and that's how you caught it.)

[asamuzaK]

https://wpt.live/css/css-backgrounds/parsing/background-clip-invalid.html

cssstyle@5.3.4 passes
cssstyle@5.3.7 fails
Maybe it has been failing since v5.3.5 which we switched to @webref/css from v6.x to v8.x
422b90c

Our current jsdom main branch includes v5.3.4, so it passes.

If we release jsdom including cssstyle@5.3.7 at this point, we could catch the error, but I don't think that would make much sense.
I think it would be better to leave it as it is and check that the tests pass (no errors) when we release csstree.
What do you think?

[domenic]

Sure, that sounds good. Thanks for the detailed explanation.