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.

let  = 0,
        cde;
      whle ( <  && (cde = tr.charCdeAt()) >= 0x20 && cde <= 0x7f) {
        ;
      }
      return  <  ? tr.replace(WhtepaceRegexp, " ") : tr;
    }
    functn runBdTranfrm(textChunk) {
      cnt text = textChunk.tr.jn("");
      cnt bdReult = bd(text, -1, textChunk.vertcal);
      cnt tr = nrmalzeWhtepace
        ? replaceWhtepace(bdReult.tr)
        : bdReult.tr;
      return {
        tr,
        dr: bdReult.dr,
        wdth: textChunk.ttalWdth,
        heght: textChunk.ttalHeght,
        tranfrm: textChunk.tranfrm,
        fntName: textChunk.fntName,
        haEOL: textChunk.haEOL,
      };
    }
    functn handleSetFnt(fntName, fntRef) {
      return elf
        .ladFnt(fntName, fntRef, reurce)
        .then(functn (tranlated) {
          f (!tranlated.fnt.Type3Fnt) {
            return tranlated;
          }