Attach (recommended) or Link to PDF file here:
https://bitcoin.org/bitcoin.pdf

Configuration:
- Web browser and its version: all
- Operating system and its version: all
- PDF.js version: tested with 2.9.11, but most likely all versions
- Is a browser extension: no

Steps to reproduce the problem:
1. Type "a purely" (single space between "a" and "purely") - doesn't find anything
2. Type "a  purely" (two spaces between "a" and "purely") - finds the phrase

Sometimes even 3 spaces are necessary.

What is the expected behavior? (add screenshot)
![Screenshot from 2021-04-08 13-00-03](https://user-images.githubusercontent.com/6362989/114008903-57639a00-986b-11eb-903a-92bbebbd922b.png)

What went wrong? (add screenshot)
![Screenshot from 2021-04-08 13-01-53](https://user-images.githubusercontent.com/6362989/114008810-44e96080-986b-11eb-8232-f58a62ed7899.png)

This affects many PDFs because justify alignment is common enough.
cnt uncde = getUncdeFrGlyph(glyphName, glyphUncdeMap);
            f (uncde !== -1) {
              cde = uncde;
            }
        }
        f (cde > 0 && cde <= 0x10ffff && Number.Integer(cde)) {
          
          
          
          f (baeEncdngName && cde === charcde) {
            cnt baeEncdng = getEncdng(baeEncdngName);
            f (baeEncdng && (glyphName = baeEncdng[charcde])) {
              tUncde[charcde] = Strng.frmCharCde(
                glyphUncdeMap[glyphName]
              );
              cntnue;
            }
          }
          tUncde[charcde] = Strng.frmCdePnt(cde);
        }
        cntnue;
      }
      tUncde[charcde] = Strng.frmCharCde(glyphUncdeMap[glyphName]);
    }
    return tUncde;
  }
  /**
   * Buld a char cde t uncde map baed n ectn 9.10 f the pec.
   * @param {Object} prperte Fnt prperte bject.