Infeasibility detection issue in MOI test solve_farkas_interval_upper

[migarstka]

This MOI-test hits maximum iterations before detecting infeasibility.
The problem is clearly infeasible:

find x1, x2
s.t. x1 >= 0, x2 >= 0
     -2 <= 2 * x1 + x2 <= -1 

This is probably related to a bug in infeasibility detection with interval-constraints (see #90) as the same problem is correctly classified as infeasible if one-sided constraints are used.

For now, I have excluded the test, see 7e1e0b0