Attempt to fix tests by increasing n_sweeps
Created by: PhilipVinc
This was done in collaboration with Damian
Our sampling tests do not take into account the fact that samples are autocorrelated. Therefore they are doomed to fail (the gaussian/continuous space even more than the discrete test).
I increase the n_sweeps to reduce autocorrelation to avoid this for the samplers that were failing the test and added a warning comment about this so that we don't forget about it