native 0.1.20 使用Graphics导致崩溃

[jkd2972]

native 0.1.20 ，Shape对象，使用Graphics绘制一个矩形。运行后，点击这个矩形。崩溃。

[jkd2972]

let rect = new egret.Shape();
rect.width = this.stage.stageWidth;
rect.height = this.stage.stageHeight;
rect.touchEnabled = true;
let g = rect.graphics;
g.beginFill(0x0000ff);
g.drawRect(0, 0, this.stage.stageWidth, this.stage.stageHeight);
g.endFill();
this.addChild(rect);