Fix the SceneSpec/debugShowBoundingVolume test with a more robust one
Fix the SceneSpec/debugShowBoundingVolume test with a more robust one

Previously, the test rendered a very large bounding box centered at
origin and radius as the distance to the camera from origin - 10.
Now, the bounding sphere is much smaller and much closer to the camera
and hence we can be sure of the bounding sphere being rendered.

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