Provide a clone method to the specialized geometries in
src/extras/geometry, otherwise:
- the `.parameters` are not copied
- the `.type` of the clone is "Geometry" or "BufferGeometry"
- the cloned object is not an instance of the initial type. It loses its
specialization and becomes a plain `Geometry` or `BufferGeometry`.

Class deriving from `PolyhedronGeometry` defined  `this.parameters` all
over the place. Standardize to defining the `.type` and `.parameters`
after the `PolyhedronGeometry` constructor is called.

Also fix prototype inheritance chain for classes deriving from
`PolyhedronGeometry`.

Fixes #5570

Keeping the old IcosahadrenGeometry and OctahedronGeometry to double check results later.