Temporarily remove Arnold font from tests #119
Description
Lately, every CI build is affected by the same error for LilyPond 2.19, see for example here. The error is due to the Arnold font not being part of fonts.openlilylib.org, as mentioned here.
Since this is not an error in OpenLilyLib code, I think that tests using the Arnold font should be disabled until the font is actually part of the distribution.