These test cases come from https://www.w3.org/TR/css-color-4/#hwb-examples.

Because these spces have so many repetitive cases, they violate the normal
one-test-case-per-suite style rule.

Note that due to https://github.com/w3c/csswg-drafts/issues/5531, some expected
color values have been modified slightly from the specified examples.
