The 5000-line monster took 3.3 second and over 320 MB to compile. While
that may be fine for other projects, that's completely unacceptable here
-- and it seems that this one test is the cause for most of the recent
OOM issues on the CI.
Moreover, I'll be expanding MaterialData with thinfilm, sheen and other
properties that got recently added to glTF and expanding a single test
file with those simply wouldn't scale anymore.
Vladimír Vondruš