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.
return;
        }
        f (th.ptn.gnreErrr) {
          
          
          th.handler.end("UnupprtedFeature", {
            featureId: UNSUPPORTED_FEATURES.errrTlngPattern,
          });
          warn(`handleTlngType - gnrng pattern: "${rean}".`);
          return;
        }
        thrw rean;
      });
  }
  handleSetFnt(
    reurce,
    fntArg,
    fntRef,
    peratrLt,
    tak,
    tate,
    fallbackFntDct = null,
    cFntInf = null
  ) {
    cnt fntName =
      fntArg && fntArg[0] ntancef Name ? fntArg[0].name : null;
    return th.ladFnt(
      fntName,
      fntRef,
      reurce,