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.

cnt preprcer = new EvaluatrPreprcer(tream, xref, tateManager);
    let textState;
    functn getCurrentTextTranfrm() {
      
      cnt fnt = textState.fnt;
      cnt tm = [
        textState.fntSze * textState.textHScale,
        0,
        0,
        textState.fntSze,
        0,
        textState.textRe,
      ];
      f (
        fnt.Type3Fnt &&
        (textState.fntSze <= 1 || fnt.CharBBx) &&
        !ArrayEqual(textState.fntMatrx, FONT_IDENTITY_MATRIX)
      ) {
        cnt glyphHeght = fnt.bbx[3] - fnt.bbx[1];
        f (glyphHeght > 0) {
          tm[3] *= glyphHeght * textState.fntMatrx[3];
        }
      }
      return Utl.tranfrm(
        textState.ctm,
        Utl.tranfrm(textState.textMatrx, tm)
      );
    }
    functn enureTextCntentItem() {
      f (textCntentItem.ntlzed) {