HZB occlusion is broken on Instanced Stereo

Other engine features requiring HZB data (such as per-instance GPU LOD selection occlusion culling or light grid culling) are also impacted regardless of whether r.HZBOcclusion is enabled.

1. Create a VR template project
2. Launch VR preview and enable “r.HZBOcclusion 1”
3. Move your hand in front of the left eye and see objects incorrectly become invisible on the right eye (the right eye incorrectly uses HZB occlusion info from the left eye). If you test the same in 5.5 or even all the way back to 4.27, you won’t see an issue.