BUG: fix an infinite loop in itk::VoronoiDiagram2DGenerator

The loop exit condition was present in the code, but never wired and removed via cd97879

Fixes #4386

Author: ILoveGoulash

Modules/Segmentation/Voronoi/include/itkVoronoiDiagram2DGenerator.hxx

@@ -274,8 +274,10 @@ VoronoiDiagram2DGenerator<TCoordinate>::ConstructDiagram()
     buildEdges.push_back(curr);
     EdgeInfo front = curr;
     EdgeInfo back = curr;
-    while (!(rawEdges[i].empty()))
+    auto     maxStop = static_cast<int>(rawEdges[i].size());
+    while (!(rawEdges[i].empty()) && (maxStop > 0))
     {
+      --maxStop;
       curr = rawEdges[i].front();
       rawEdges[i].pop_front();
       unsigned char frontbnd = Pointonbnd(front[0]);