Steps to reproduce (this PDF):
[page4.pdf](https://github.com/mozilla/pdf.js/files/5990272/page4.pdf)

````
npm install
node_modules/.bin/gulp dist-install
node examples/node/pdf2svg.js /tmp/page4.pdf
````

Error:
````
Error: Invalid SVG dimensions
    at unreachable (/tmp/pdf.js/build/dist/legacy/build/pdf.js:2086:9)
    at assert (/tmp/pdf.js/build/dist/legacy/build/pdf.js:2091:5)
    at DOMSVGFactory.create (/tmp/pdf.js/build/dist/legacy/build/pdf.js:640:24)
    at SVGGraphics._makeTilingPattern (/tmp/pdf.js/build/dist/legacy/build/pdf.js:24178:36)
    at SVGGraphics._makeColorN_Pattern (/tmp/pdf.js/build/dist/legacy/build/pdf.js:24127:23)
    at SVGGraphics.setFillColorN (/tmp/pdf.js/build/dist/legacy/build/pdf.js:24088:39)
    at SVGGraphics.executeOpTree (/tmp/pdf.js/build/dist/legacy/build/pdf.js:23634:22)
    at /tmp/pdf.js/build/dist/legacy/build/pdf.js:23508:18
    at process._tickCallback (internal/process/next_tick.js:68:7)
    at Function.Module.runMain (internal/modules/cjs/loader.js:834:11)
````
break;
          case "ca":
            this.setFillAlpha(value);
            break;
          default:
            warn(`Unimplemented graphic state operator ${key}`);
            break;
        }
      }
    }
    fill() {
      const current = this.current;
      if (current.element) {
        current.element.setAttributeNS(null, "fill", current.fillColor);
        current.element.setAttributeNS(null, "fill-opacity", current.fillAlpha);
        this.endPath();
      }
    }
    stroke() {
      const current = this.current;
      if (current.element) {
        this._setStrokeAttributes(current.element);
        current.element.setAttributeNS(null, "fill", "none");
        this.endPath();
      }
    }
    /**
     * @private
     */
    _setStrokeAttributes(element, lineWidthScale = 1) {