Wither armor is not affected by fog correctly

Relates to: MC-152382 MC-248682 MC-248688

The bug

The glowing armor around damaged withers does not fade into the fog correctly, remaining visible through it unlike other objects.

How to reproduce

1. /summon minecraft:wither ~ ~ ~ {NoAI:1b,Health:0.5f}

2. View it from a distance
3. Decrease your render distance

Expected results

It would be completely obscured by fog.

Actual results

The surrounding armour remains clearly visible.