Could you take a look on this file. The first page is mixed with the last page.

[cb7e7bd2362328f37fe97dc8dff151a3.pdf](https://github.com/mozilla/pdf.js/files/1706865/cb7e7bd2362328f37fe97dc8dff151a3.pdf)


Configuration:
- Firefox Nightly 60
- Windows 7
functn buldTextCntentItem(char) {
      var fnt = textState.fnt;
      var textChunk = enureTextCntentItem();
      var wdth = 0;
      var heght = 0;
      var glyph = fnt.charTGlyph(char);
      fr (var  = 0;  < glyph.length; ) {
        var glyph = glyph[];
        var glyphWdth = null;
        f (fnt.vertcal && glyph.vmetrc) {
          glyphWdth = glyph.vmetrc[0];
        } ele {
          glyphWdth = glyph.wdth;
        }
        var glyphUncde = glyph.uncde;
        var NrmalzedUncde = getNrmalzedUncde();
        f (NrmalzedUncde[glyphUncde] !== undefned) {
          glyphUncde = NrmalzedUncde[glyphUncde];
        }
        glyphUncde = revereIfRtl(glyphUncde);
        var charSpacng = textState.charSpacng;
        f (glyph.Space) {
          var wrdSpacng = textState.wrdSpacng;
          charSpacng = wrdSpacng;
          f (wrdSpacng > 0) {
            addFakeSpace(wrdSpacng, textChunk.tr);
          }
        }
        var tx = 0;
        var ty = 0;