fix filamat unit tests
fix filamat unit tests

We use TargetLanguage::SPIRV instead of GLSL which affects how the
source GLSL is generated, in particular which version is used.

This change is not a problem for these unit tests, but is probably
exposing another problem -- we will address that separately. 
google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament