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)
````
}
      
      const clipId = `clippath${clipCount++}`;
      const clipPath = this.svgFactory.createElement("svg:clipPath");
      clipPath.setAttributeNS(null, "id", clipId);
      clipPath.setAttributeNS(null, "transform", pm(this.transformMatrix));
      
      const clipElement = current.element.cloneNode(true);
      if (this.pendingClip === "evenodd") {
        clipElement.setAttributeNS(null, "clip-rule", "evenodd");
      } else {
        clipElement.setAttributeNS(null, "clip-rule", "nonzero");
      }
      this.pendingClip = null;
      clipPath.appendChild(clipElement);
      this.defs.appendChild(clipPath);
      if (current.activeClipUrl) {
        
        
        current.clipGroup = null;
        for (const prev of this.extraStack) {
          prev.clipGroup = null;
        }
        
        clipPath.setAttributeNS(null, "clip-path", current.activeClipUrl);
      }
      current.activeClipUrl = `url(#${clipId})`;
      this.tgrp = null;
    }
    clip(type) {