Add reference file for font case

[chenxix]

[syncbot]

Automatic validation checks of commit 4058628 passed.

[syncbot]

Automatic validation checks of commit c8efab9 passed.

[syncbot]

Automatic validation checks of commit fddd33f passed.

[syncbot]

Automatic validation checks of commit 6a15582 passed.

[zqzhang]

Lines 10~12 use the same technology to be tested. This is not a good reference file.

[chenxix]

This case is to check if the 'font' shorthand property can accept and set font-variant, font-size and font-family at the same time. So I set these 3 attributes one by one. Is there some other way to set the same font style ?

[zqzhang]

For the Ahem font usage, please refer to http://testthewebforward.org/docs/test-style-guidelines.html#special-fonts

[Ms2ger]

Reviewed 11 of 11 files at r1.
Review status: all files reviewed at latest revision, 2 unresolved discussions, all commit checks successful.

---

^{css21/fonts/font-033-ref.html, line 7 [r1] (raw file):}
I don't think anything guarantees that caption is equivalent to sans-serif (feel free to correct me if I'm wrong). If I'm right, though, I don't think we can write a useful reference for this range of tests.

---

^{css21/fonts/font-044-ref.html, line 8 [r1] (raw file):}
I'm afraid this isn't really a useful reference, since a bug would likely cause the reference to fail in the same way as the test itself.

---

Comments from the review on Reviewable.io

[Ms2ger]

Thank you for your PR.

I landed the font-003 reference in #869. I don't believe the approach takes here for other tests can work, so I'm closing this PR. If you can come up with a workable approach, please do!