Refactor `GetByteSize` and `GetPlaneByteSize` using `GetBlockShape`
Refactor `GetByteSize` and `GetPlaneByteSize` using `GetBlockShape`

This eliminates a substantial amount duplicate code between `GetByteSize` and
`GetBlockShape`.

Also added explicit tests of `GetPlateByteSize` independent of `GetByteSize`.

baldurk/renderdoc,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,googlestadia/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,baldurk/renderdoc,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,baldurk/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,Zorro666/renderdoc