D1882/rP22817 optimised MakeGoalReachable, but unfortunately I sorted regions by distance to the origin and not the goal, breaking the algorithm for the unreachable case.
This fixes it and adds a regression test (a new test case anyways). The test map wasn't big enough to properly detect this...
This bug was reported by faction02 in a forum https://wildfiregames.com/forum/index.php?/messenger/10014/ following an svn testgame