0027873: Exception is raised in BRepFill_Filling::FindExtremitiesOfHoles()

The reason of exception has been eliminated.
Creation of the test case for this issue.
Correction of unstable test case.

Some test cases have been adjusted according to their new behavior.

src/BRepFill/BRepFill_Filling.cxx

@@ -479,11 +479,20 @@ void BRepFill_Filling::FindExtremitiesOfHoles(const TopTools_ListOfShape& WireLi
   theWire = TopoDS::Wire(WireSeq(1));
   WireSeq.Remove(1);
 
-  if (theWire.Closed())
+  if (BRep_Tool::IsClosed(theWire))
     return;
 
   TopoDS_Vertex Vfirst, Vlast;
   TopExp::Vertices( theWire, Vfirst, Vlast );
+
+  if (Vfirst.IsSame(Vlast))
+  {
+    // The Wire is closed indeed despite its 
+    // being not detected earlier.
+
+    return;
+  }
+
   gp_Vec FinVec = MakeFinVec( theWire, Vlast );
   TopoDS_Vertex theVertex = Vlast;
   VerSeq.Append( Vlast );