Move maxiter check after the feasible_tree() call.

Move maxiter check after the feasible_tree() call.

Edit from Matt: changelog entry and un-xfailed the test case.

Quoting the description of MR !1688 if it ever ends up lost to the sands of
time:

  If `nslimit1` is zero, then `rank2` is called with `maxiter=0`. It is likely
  the intent here is to at least compute and return an initial feasible solution
  (though not running any network simplex iterations).

Gitlab: fixes #1902

Co-authored-by: Matthew Fernandez <matthew.fernandez@gmail.com>