[cairo] rendering changes cairo 1.16 -> 1.17.4

[Felix Schwarz]

Hi Uli,

Am 01.03.21 um 12:46 schrieb Uli Schlachter:
> (Note that in both cases there was a warning: WARNING: Font-face
> "weasyprint" cannot be loaded)

Maybe you can try the simpler HTML from my "minimal" example:
https://github.com/FelixSchwarz/cairo117-repro/blob/main/minimal.py

Also you need the "AHEM____.TTF" in the same directory and that is a special 
font used for testing: https://web-platform-tests.org/writing-tests/ahem.html

(not sure about the .otf font. That one is new and I'm not sure if Debian's 
WeasyPrint can handle it already.)

Thank you for your help.

Felix