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)
````
current.path &&
        ops.length > 0 &&
        ops[0] !== OPS.rectangle &&
        ops[0] !== OPS.moveTo
      ) {
        
        
        
        d = current.path.getAttributeNS(null, "d") + d;
      } else {
        current.path = this.svgFactory.createElement("svg:path");
        this._ensureTransformGroup().appendChild(current.path);
      }
      current.path.setAttributeNS(null, "d", d);
      current.path.setAttributeNS(null, "fill", "none");
      
      
      current.element = current.path;
      current.setCurrentPoint(x, y);
    }
    endPath() {
      const current = this.current;
      
      current.path = null;
      if (!this.pendingClip) {
        return;
      }
      if (!current.element) {
        this.pendingClip = null;
        return;