Attach (recommended) or Link to PDF file here: https://www.recom-power.com/pdf/Powerline-AC-DC/RAC05-K.pdf

Configuration:
- Web browser and its version: Firefox 56.0 (64-bit)
- Operating system and its version: Windows 10 with OS Build 15063.632
- PDF.js version: ?
- Is an extension: Built-in

Steps to reproduce the problem:
1. Open Page

What is the expected behavior? To properly render the first page. 
![image](https://user-images.githubusercontent.com/1151969/31415345-b1504022-add7-11e7-855b-8030a308f7a2.png)

What went wrong? Renders poorly.
![image](https://user-images.githubusercontent.com/1151969/31415363-d8842096-add7-11e7-818d-728c1102891b.png)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension): ?

const activeSMask = this.current.activeSMask;
    const drawnWidth = activeSMask.canvas.width;
    const drawnHeight = activeSMask.canvas.height;
    const cacheId = "smaskGroupAt" + this.groupLevel;
    const scratchCanvas = this.cachedCanvases.getCanvas(
      cacheId,
      drawnWidth,
      drawnHeight,
      true
    );
    const currentCtx = this.ctx;
    const currentTransform = currentCtx.mozCurrentTransform;
    this.ctx.save();
    const groupCtx = scratchCanvas.context;
    groupCtx.scale(1 / activeSMask.scaleX, 1 / activeSMask.scaleY);
    groupCtx.translate(-activeSMask.offsetX, -activeSMask.offsetY);
    groupCtx.transform.apply(groupCtx, currentTransform);
    activeSMask.startTransformInverse = groupCtx.mozCurrentTransformInverse;
    copyCtxState(currentCtx, groupCtx);
    this.ctx = groupCtx;
    this.setGState([
      ["BM", "source-over"],
      ["ca", 1],
      ["CA", 1],
    ]);
    this.groupStack.push(currentCtx);
    this.groupLevel++;
  }
  suspendSMaskGroup() {