Link to PDF file (or attach file here):
[pages4.pdf](https://github.com/mozilla/pdf.js/files/1128300/pages4.pdf)

Configuration:
- Web browser and its version: Firefox 54
- Operating system and its version: Win 10
- PDF.js version: 1.8.522
- Is an extension: no

What is the expected behavior? (add screenshot)
![chrome1-1 1](https://user-images.githubusercontent.com/146436/27918380-2f74512a-6245-11e7-8525-d0038fa6c2e8.jpg)
![chrome1-2 1](https://user-images.githubusercontent.com/146436/27918425-54f8e47e-6245-11e7-9bff-127f79ad0511.jpg)


What went wrong? (add screenshot)
![screenshot from 2017-07-06 12-10-30](https://user-images.githubusercontent.com/146436/27918442-5d57624e-6245-11e7-9436-5ba31cc8bd1a.png)
![screenshot from 2017-07-06 12-10-44](https://user-images.githubusercontent.com/146436/27918454-63b486da-6245-11e7-9eb5-c03aa5c40943.png)



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) {