Panic with continuous collision detection with HeightMap in time_of_impact

https://github.com/rustsim/ncollide/blob/a834dfd986a48f0c5bb27745a60e1c08e70e993d/src/query/time_of_impact/time_of_impact.rs#L150
This is triggered in nphysics by having a height map collider and for example a ball on which ccd is enabled.
From an api perspective it is weird that the function would panic instead of returning an error if the case cannot be handled.
This is probably known to the author seeing as ccd is supported for `TriMesh` through `as_support_map` and that a similar implementation was started for height map but commented out. Having the issue it might help other users.