Attach (recommended) or Link to PDF file here:
[example.pdf](https://github.com/mozilla/pdf.js/files/6916129/example.pdf)

Configuration:
- Web browser and its version: Chrome, Firefox
- Operating system and its version: all
- PDF.js version: various versions, including 2.11.54
- Is a browser extension: no

Screenshot with visible textLayer:
![Screenshot from 2021-08-02 13-05-03](https://user-images.githubusercontent.com/6362989/127844878-f85e291f-2060-4028-be09-7835f32ccfaa.png)

Which means some letters at the beginning/end of text selection are missing when copying text.

const start = (font.start ? font.start : 0) + nameTable.offset;
      font.pos = start;
      const names = [[], []];
      const length = nameTable.length,
        end = start + length;
      const format = font.getUint16();
      const FORMAT_0_HEADER_LENGTH = 6;
      if (format !== 0 || length < FORMAT_0_HEADER_LENGTH) {
        
        return names;
      }
      const numRecords = font.getUint16();
      const stringsStart = font.getUint16();
      const records = [];
      const NAME_RECORD_LENGTH = 12;
      let i, ii;
      for (i = 0; i < numRecords && font.pos + NAME_RECORD_LENGTH <= end; i++) {
        const r = {
          platform: font.getUint16(),
          encoding: font.getUint16(),
          language: font.getUint16(),
          name: font.getUint16(),
          length: font.getUint16(),
          offset: font.getUint16(),
        };