Ensure algorithmic safety (KICAD-ARX).

(cherry picked from commit 5ab735eb93)

pcbnew/pcb_track.cpp

@@ -1920,7 +1920,7 @@ VECTOR2I PCB_ARC::GetPosition() const
 double PCB_ARC::GetRadius() const
 {
     auto center = CalcArcCenter( m_Start, m_Mid , m_End );
-    return center.Distance( m_Start );
+    return std::min( center.Distance( m_Start ), INT_MAX / 2.0 );
 }