uilayout clipping issue in latest code

[fresair]

• cocos2d-x version:newest code on git (version commit 023b172 6 hours ago is not good. version 3.17.1 is going well)
• devices test on: iphone 6sp and some simulators
• developing environments
  • NDK version:
  • Xcode version:10.2.1
  • VS version:
  • browser type and version:

Steps to Reproduce:

add following code in hello world project
1.

var bg = new ccui.Layout();
bg.setAnchorPoint(0, 0);
bg.setTag(125);
bg.setContentSize(cc.size(300, 60));//300
bg.setClippingEnabled(true);
                                      
var imagetest=new cc.Sprite(res.HelloWorld_png);
imagetest.setAnchorPoint(0, 0);
 imagetest.setPosition(0, 0);
bg.addChild(imagetest);
bg.setPosition(size.width / 2+100, size.height / 2);
this.addChild(bg);
bg.setContentSize(cc.size(300, 60));

2. if the last line x value not 0 (in the above code is 300) , the code behave well, clipping is ok.
   But if use 0 like bg.setContentSize(cc.size(0, 60)); clipping not work, you still can see the attached image which supposed to hidden totally.

[fresair]

in CCDrawNode.cpp
I roll back cursor = Triangulate::processTriangles(verts,cursor,count,fillColor); to old function blew, then the uilayout behave ok again.

for (int i = 0; i < count-2; i++)
{
V2F_C4B_T2F_Triangle tmp = {
{verts[0], Color4B(fillColor), __t(v2fzero)},
{verts[i+1], Color4B(fillColor), __t(v2fzero)},
{verts[i+2], Color4B(fillColor), __t(v2fzero)},
};

        *cursor++ = tmp;
    }