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 current = this.current;
      const fontObj = this.commonObjs.get(details[0]);
      let size = details[1];
      current.font = fontObj;
      if (
        this.embedFonts &&
        !fontObj.missingFile &&
        !this.embeddedFonts[fontObj.loadedName]
      ) {
        this.addFontStyle(fontObj);
        this.embeddedFonts[fontObj.loadedName] = fontObj;
      }
      current.fontMatrix = fontObj.fontMatrix || FONT_IDENTITY_MATRIX;
      let bold = "normal";
      if (fontObj.black) {
        bold = "900";
      } else if (fontObj.bold) {
        bold = "bold";
      }
      const italic = fontObj.italic ? "italic" : "normal";
      if (size < 0) {
        size = -size;
        current.fontDirection = -1;
      } else {