tu: enhanced layout xfb fails
These currently fail, but I think they should be passing:
KHR-Single-GL46.enhanced_layouts.xfb_capture_inactive_output_block_member,Fail
KHR-Single-GL46.enhanced_layouts.xfb_capture_struct,Fail
KHR-Single-GL46.enhanced_layouts.xfb_vertex_streams,Fail
May need !17102 (merged) in order to avoid hanging/crashing.