Attach (recommended) or Link to PDF file here:  [test.pdf](https://akmer.aikucun.com/a94a8fe5ccb19ba61c4c0873d391e987982fbbd3_1616477914120_83.pdf)


Configuration:
- Web browser and its version: chrome 87.0.4280.88
- Operating system and its version: windows10
- PDF.js version: 2.6.347
- Is a browser extension:

Steps to reproduce the problem:
1. just open 

What is the expected behavior? (add screenshot)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/17724610/112087066-473f8f80-8bc8-11eb-8efb-56139ec42a9c.png)

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

for (var i = tableState.entryNum; i < count; i++) {
          tableState.streamPos = stream.pos;
          tableState.entryNum = i;
          tableState.parserBuf1 = parser.buf1;
          tableState.parserBuf2 = parser.buf2;
          var entry = {};
          entry.offset = parser.getObj();
          entry.gen = parser.getObj();
          var type = parser.getObj();
          if (type instanceof Cmd) {
            switch (type.cmd) {
              case "f":
                entry.free = true;
                break;
              case "n":
                entry.uncompressed = true;
                break;
            }
          }
          
          if (
            !Number.isInteger(entry.offset) ||
            !Number.isInteger(entry.gen) ||
            !(entry.free || entry.uncompressed)
          ) {
            throw new FormatError(
              `Invalid entry in XRef subsection: ${first}, ${count}`
            );
          }