Tilesets render black when scaled down in built-in render pipeline

This happens when you add a Cesium World Terrain w/ Bing Maps Imagery to the scene, then scale it down to 0.00006 in all three components (you may have to do so slowly, because the double-click to zoom function doesn't account for the new size).

This is a known issue based on the presence of multiple forum threads ([x](https://forum.unity.com/threads/textures-not-rendered-when-model-is-scaled-down.451451/), [x](https://forum.unity.com/threads/objects-with-small-scale-turn-black.1225566/), [x](https://forum.unity.com/threads/materials-turn-black-on-scaling.752732/)), but I don't know what the solution would be here. This issue on the [Mapbox Unity SDK](https://github.com/mapbox/mapbox-unity-sdk/issues/42) came up while I was searching for answers -- they suggest its a floating precision issue with the lighting system. That might be what's happening -- the tiles are so thin it's causing rendering artifacts.