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)
````
this.save();
      this.executeOpTree(items);
      this.restore();
    }
    loadDependencies(operatorList) {
      const fnArray = operatorList.fnArray;
      const argsArray = operatorList.argsArray;
      for (let i = 0, ii = fnArray.length; i < ii; i++) {
        if (fnArray[i] !== OPS.dependency) {
          continue;
        }
        for (const obj of argsArray[i]) {
          const objsPool = obj.startsWith("g_") ? this.commonObjs : this.objs;
          const promise = new Promise(resolve => {
            objsPool.get(obj, resolve);
          });
          this.current.dependencies.push(promise);
        }
      }
      return Promise.all(this.current.dependencies);
    }
    transform(a, b, c, d, e, f) {
      const transformMatrix = [a, b, c, d, e, f];
      this.transformMatrix = Util.transform(
        this.transformMatrix,
        transformMatrix
      );
      this.tgrp = null;
    }
    getSVG(operatorList, viewport) {