Attach (recommended) or Link to PDF file here:
[Test file.pdf](https://github.com/mozilla/pdf.js/files/4656226/Test.file.pdf)

Configuration:
- Web browser and its version: Chrome Version 81.0.4044.138 (Official Build) (64-bit)
- Operating system and its version: Windows 10
- PDF.js version: latest
- Is a browser extension: no

Steps to reproduce the problem:
1. Open [https://mozilla.github.io/pdf.js/web/viewer.html](https://mozilla.github.io/pdf.js/web/viewer.html)
2. Load the provided .pdf file

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/5569382/82438616-02c3fe80-9aa2-11ea-9003-b75ea1e7aac6.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5569382/82438640-09527600-9aa2-11ea-810b-071da7e37896.png)


);
      this.ctx.restore();
      this.ctx.save(); 
      copyCtxState(groupCtx, this.ctx);
      
      this.current.resumeSMaskCtx = groupCtx;
      
      
      const deltaTransform = Util.transform(
        this.current.activeSMask.startTransformInverse,
        groupCtx.mozCurrentTransform
      );
      this.ctx.transform.apply(this.ctx, deltaTransform);
      
      groupCtx.save();
      groupCtx.setTransform(1, 0, 0, 1, 0, 0);
      groupCtx.clearRect(0, 0, groupCtx.canvas.width, groupCtx.canvas.height);
      groupCtx.restore();
    },
    resumeSMaskGroup: function CanvasGraphics_resumeSMaskGroup() {
      
      
      
      const groupCtx = this.current.resumeSMaskCtx;
      const currentCtx = this.ctx;
      this.ctx = groupCtx;
      this.groupStack.push(currentCtx);
      this.groupLevel++;
    },
    endSMaskGroup: function CanvasGraphics_endSMaskGroup() {