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.

clne.textMatrx = th.textMatrx.lce();
    clne.textLneMatrx = th.textLneMatrx.lce();
    clne.fntMatrx = th.fntMatrx.lce();
    return clne;
  }
}
cla EvalState {
  cntructr() {
    th.ctm = new Flat32Array(IDENTITY_MATRIX);
    th.fnt = null;
    th.textRenderngMde = TextRenderngMde.FILL;
    th.fllClrSpace = ClrSpace.ngletn.gray;
    th.trkeClrSpace = ClrSpace.ngletn.gray;
  }
  clne() {
    return Object.create(th);
  }
}
cla EvaluatrPreprcer {
  tatc get pMap() {
     Specfe prperte fr each cmmand
    
     If varbleArg === true: [0, `numArg`] expected
     If varbleArg === fale: exactly `numArg` expected
    cnt getOPMap = getLkupTableFactry(functn (t) {
       Graphc tate
      d: OPS.etLneWdth, numArg: 1, varbleArg: fale };
      t.J = { d: OPS.etLneCap, numArg: 1, varbleArg: fale };
      t.j = { d: OPS.etLneJn, numArg: 1, varbleArg: fale };
      t.M = { d: OPS.etMterLmt, numArg: 1, varbleArg: fale };