[cssom] Updated test cases to review

Hi all,

I've spent the past couple days revising CSSOM test cases to ensure
conformance with the spec and maintaining spec links. I currently have four
open pull requests that need review, and since there is only one current
editor of the spec, I wanted to reach out to see if anyone was willing to
look through the changes. The PRs are as follows:

https://github.com/w3c/web-platform-tests/pull/9958
https://github.com/w3c/web-platform-tests/pull/9960
https://github.com/w3c/web-platform-tests/pull/10005
https://github.com/w3c/web-platform-tests/pull/10014

Thanks,
Chris