Speed up OCT tests
Pack states in propagation functions if StatesPack=yes and if it is allowed by the hamiltonian. Use this in all OCT tests. This makes the tests much faster for GPU runs.
For the longest tests, use the Taylor expansion for the exponential because it is much faster when using GPUs.
Make OCT tests faster.
- I have checked that my code follows the Octopus coding standards
- I have added tests for all the new features added in this request.