Partial revert to solve hang.

The exact points are used as start and end-points later on to resolve the total begin/end of the entire loop. So, revert this small improvement that has little to nothing to do with the issue at hand itself.

done as part of CURA-10410

src/infill.cpp

@@ -836,7 +836,6 @@ void Infill::connectLines(Polygons& result_lines)
         }
     }
 
-    constexpr coord_t epsilon_squared = 25;
     const auto half_line_distance_squared = (line_distance * line_distance) / 4;
     for (size_t polygon_index = 0; polygon_index < inner_contour.size(); polygon_index++)
     {
@@ -898,8 +897,7 @@ void Infill::connectLines(Polygons& result_lines)
 
                     InfillLineSegment* new_segment;
                     // If the segment is near zero length, we avoid creating it but still want to connect the crossing with the previous segment.
-                    const auto connect_distance_squared = vSize2(previous_point - next_point);
-                    if (connect_distance_squared < epsilon_squared)
+                    if (previous_point == next_point)
                     {
                         (previous_forward ? previous_segment->previous : previous_segment->next) = crossing;
                         new_segment = previous_segment;
@@ -908,7 +906,7 @@ void Infill::connectLines(Polygons& result_lines)
                     {
                         // Resolve any intersections of the fill lines close to the boundary, by inserting extra points so the lines don't create a tiny 'loop'.
                         Point intersect;
-                        if (connect_distance_squared < half_line_distance_squared
+                        if (vSize2(previous_point - next_point) < half_line_distance_squared
                             && LinearAlg2D::lineLineIntersection(previous_segment->start, previous_segment->end, crossing->start, crossing->end, intersect)
                             && LinearAlg2D::pointIsProjectedBeyondLine(intersect, previous_segment->start, previous_segment->end) == 0
                             && LinearAlg2D::pointIsProjectedBeyondLine(intersect, crossing->start, crossing->end) == 0)
@@ -939,7 +937,7 @@ void Infill::connectLines(Polygons& result_lines)
 
                 const bool choose_side = (vertex_index == previous_segment->start_segment && polygon_index == previous_segment->start_polygon);
                 const auto& previous_side = choose_side ? previous_segment->start : previous_segment->end;
-                if (vSize2(previous_side - vertex_after) < epsilon_squared)
+                if (previous_side == vertex_after)
                 {
                     // Edge case when an infill line ends directly on top of vertex_after: We skip the extra connecting line segment, as that would be 0-length.
                     previous_segment = nullptr;