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)

const [x1, y1, r1, x2, y2, r2] = this.coordsArr;
      const distance = Math.hypot(x1 - x2, y1 - y2);
      if (r1 <= r2 + distance && r2 <= r1 + distance) {
        warn("Unsupported radial gradient.");
      }
    }
    this.extendStart = extendStart;
    this.extendEnd = extendEnd;
    const fnObj = dict.getRaw("Function");
    const fn = pdfFunctionFactory.createFromArray(fnObj);
    
    
    
    const NUMBER_OF_SAMPLES = 10;
    const step = (t1 - t0) / NUMBER_OF_SAMPLES;
    const colorStops = (this.colorStops = []);
    
    if (t0 >= t1 || step <= 0) {
      
      
      info("Bad shading domain.");
      return;
    }
    const color = new Float32Array(cs.numComps),
      ratio = new Float32Array(1);
    let rgbColor;
    for (let i = 0; i <= NUMBER_OF_SAMPLES; i++) {
      ratio[0] = t0 + i * step;