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)
````
if (Array.isArray(matrix) && matrix.length === 6) {
        this.transform(
          matrix[0],
          matrix[1],
          matrix[2],
          matrix[3],
          matrix[4],
          matrix[5]
        );
      }
      if (bbox) {
        const width = bbox[2] - bbox[0];
        const height = bbox[3] - bbox[1];
        const cliprect = this.svgFactory.createElement("svg:rect");
        cliprect.setAttributeNS(null, "x", bbox[0]);
        cliprect.setAttributeNS(null, "y", bbox[1]);
        cliprect.setAttributeNS(null, "width", pf(width));
        cliprect.setAttributeNS(null, "height", pf(height));
        this.current.element = cliprect;
        this.clip("nonzero");
        this.endPath();
      }
    }
    paintFormXObjectEnd() {}