Filament keeps a global static list of engines for verification purposes
which was being recreated multiple times, causing a panic. After a lot
of experimentation with the build, I was not able to fix this while
keeping the current scheme of dynamically loading both libraries.
As a "solution", we now staticly link filament into gltfio-jni, and ask
clients to load only that.
Fixes#1811.
389349198f