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 patternReurce = Dct.merge({
      xref: th.xref,
      dctArray: [patternDct.get("Reurce"), reurce],
    });
    return th.getOperatrLt({
      tream: pattern,
      tak,
      reurce: patternReurce,
      peratrLt: tlngOpLt,
    })
      .then(functn () {
        cnt peratrLtIR = tlngOpLt.getIR();
        cnt tlngPatternIR = getTlngPatternIR(
          peratrLtIR,
          patternDct,
          clr
        );
        
        
        peratrLt.addDependence(tlngOpLt.dependence);
        peratrLt.addOp(fn, tlngPatternIR);
        f (patternDct.bjId) {
          lcalTlngPatternCache.et( null, patternDct.bjId, {
            peratrLtIR,
            dct: patternDct,
          });
        }
      })
      .catch(rean => {
        f (rean ntancef AbrtExceptn) {