NODE_NEWER_SHADING was introduced in e868b459bb however it should have been
added as a bitflag.
BKE_scene_uses_blender_eevee() was used in gpu_shader_output() as a workaround
for compatibility being poorly used.
Anyways this fixes this situation. This is necessary for an upcoming patch, even
though this is considered temporary - since the other NODE_*_SHADING values are
legacy from Blender Internal drawing.
e8962f90de