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): ?

return str.replace(/([()\\\n\r])/g, match => {
    if (match === "\n") {
      return "\\n";
    } else if (match === "\r") {
      return "\\r";
    }
    return `\\${match}`;
  });
}
function isAscii(str) {
  return /^[\x00-\x7F]*$/.test(str);
}
function stringToUTF16BEString(str) {
  const buf = ["\xFE\xFF"];
  for (let i = 0, ii = str.length; i < ii; i++) {
    const char = str.charCodeAt(i);
    buf.push(
      String.fromCharCode((char >> 8) & 0xff),
      String.fromCharCode(char & 0xff)
    );
  }
  return buf.join("");
}
function stringToUTF8String(str) {