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)


warn("Knockout groups not supported.");
      }
      const currentTransform = currentCtx.mozCurrentTransform;
      if (group.matrix) {
        currentCtx.transform.apply(currentCtx, group.matrix);
      }
      if (!group.bbox) {
        throw new Error("Bounding box is required.");
      }
      
      
      let bounds = Util.getAxialAlignedBoundingBox(
        group.bbox,
        currentCtx.mozCurrentTransform
      );
      
      const canvasBounds = [
        0,
        0,
        currentCtx.canvas.width,
        currentCtx.canvas.height,
      ];
      bounds = Util.intersect(bounds, canvasBounds) || [0, 0, 0, 0];
      
      
      const offsetX = Math.floor(bounds[0]);
      const offsetY = Math.floor(bounds[1]);
      let drawnWidth = Math.max(Math.ceil(bounds[2]) - offsetX, 1);
      let drawnHeight = Math.max(Math.ceil(bounds[3]) - offsetY, 1);
      let scaleX = 1,