Since tvOS 11 there's not a single font, on that platform, that
has the ligatures that the test verified.
Test remains enabled for other platforms.
reference:
https://bugzilla.xamarin.com/show_bug.cgi?id=58929
Disabled because it looks like the tvOS font we use: "Gujarati Sangam MN"
does not have rare ligatures anymore (and the entire test is based on it).
Before getting an actual fix for that, let's disable the test so it doesn't break all current builds.
See: https://bugzilla.xamarin.com/show_bug.cgi?id=58929
Sebastien Pouliot
Vincent Dondain
Timothy Risi
Rolf Bjarne Kvinge