[Backport 8.x.x] PBR Sky renderer now shares its internal precomputation table between different instances.#483

JulienIgnace-Unity merged 3 commits into8.x.x/hd/stagingUnity-Technologies/Graphics:8.x.x/hd/stagingfrom

8.x.x/hd/share-pbrsky-texturesUnity-Technologies/Graphics:8.x.x/hd/share-pbrsky-texturesCopy head branch name to clipboard