Replace C tests with Rust tests for the individual components and get rid of all C dependencies

[sdroege]

From here:

I think at some point we should simply drop the C tests as long as we have new tests that cover all the components equally well. The implementation is diverging a lot from the C implementation already and at some point keeping the outputs similar enough with all the floating point inaccuracies depending on operation order/etc this is going to be annoying to maintain.