Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Chrome 90.0.4430.93
- Operating system and its version: macOs Big Sur 11.2.3
- PDF.js version: 2.7.570
- Is a browser extension: No

Steps to reproduce the problem:
1. Load the attached pdf in https://mozilla.github.io/pdf.js/web/viewer.html
2. Go to page 46. Dotted lines are missing in the graphics (see screenshot from acrobat reader)

What is the expected behavior? (add screenshot) See the screenshot
[Technical_Guide_UK.pdf](https://github.com/mozilla/pdf.js/files/6413001/Technical_Guide_UK.pdf)
![Screenshot 2021-05-03 at 07 46 09](https://user-images.githubusercontent.com/3785784/116844541-a343fd80-abe3-11eb-94c3-d03b3dfd6769.png)

ctx.fillStyle = pattern.getPattern(ctx, this, true);
      const inv = ctx.mozCurrentTransformInverse;
      if (inv) {
        const canvas = ctx.canvas;
        const width = canvas.width;
        const height = canvas.height;
        const bl = Util.applyTransform([0, 0], inv);
        const br = Util.applyTransform([0, height], inv);
        const ul = Util.applyTransform([width, 0], inv);
        const ur = Util.applyTransform([width, height], inv);
        const x0 = Math.min(bl[0], br[0], ul[0], ur[0]);
        const y0 = Math.min(bl[1], br[1], ul[1], ur[1]);
        const x1 = Math.max(bl[0], br[0], ul[0], ur[0]);
        const y1 = Math.max(bl[1], br[1], ul[1], ur[1]);
        this.ctx.fillRect(x0, y0, x1 - x0, y1 - y0);
      } else {
        
        
        
        
        
        this.ctx.fillRect(-1e10, -1e10, 2e10, 2e10);
      }
      this.restore();
    }
    
    beginInlineImage() {
      unreachable("Should not call beginInlineImage");
    }
    beginImageData() {