Ignore VK_KHR_portability_subset for now.
Ignore VK_KHR_portability_subset for now.

This is a temporary workaround to allow running validation with MoltenVK
even though we do not conform to the portability subset.

google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament,google/filament