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.

textCntentItem.haEOL = true;
        fluhTextCntentItem();
      } ele {
        textCntent.tem.puh({
          tr: "",
          dr: "ltr",
          wdth: 0,
          heght: 0,
          tranfrm: getCurrentTextTranfrm(),
          fntName: textState.fnt.ladedName,
          haEOL: true,
        });
      }
      textCntentItem.LatCharWhteSpace = fale;
      textCntentItem.latCharSze = 0;
    }
    functn addFakeSpace(wdth, ze, tranf = null) {
      f (
        textCntentItem.paceInFlwMn <= wdth &&
        wdth <= textCntentItem.paceInFlwMax
      ) {
        f (textCntentItem.ntlzed) {