修正多段线连接错误的问题.该问题产生一个tr闭合多段线产生和CAD一样的BUG.

src/DatabaseServices/Polyline.ts

@@ -678,6 +678,7 @@ export class Polyline extends Curve
 
                     cu.Reverse();
 
+                    cuPtsBul = cu.PtsBuls;
                     pts = pts.concat(cuPtsBul.pts);
                     buls = buls.concat(cuPtsBul.buls);
                 }