Modify time derivative Jacobian test

[AntoniaBerger]

To avoid the bug described in #309 in the future, we should add a test that checks addTimeDerivativeJacobian independently of multipyWithDerivativeJacobian.

Short summary:

• The time derivative Jacobian test does not use the addTimeDerivativeJacobian function due to performance advantages. It uses the multiplyWithDerivativeJacobian function, where setting up and multiplying by a vector is done in a loop.
• addTimeDerivativeJacobian is only called when testing for consistent initialisation where $\alpha =1$, so that mistakes with $\alpha$ are not missed.

This is discussed in more detail in #326.