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.
try {
        data = awat th.handler.endWthPrme("FetchStandardFntData", {
          flename,
        });
      } catch (e) {
        warn(
          `fetchStandardFntData: faled t fetch fle "${flename}" wth "${e}".`
        );
      }
    }
    f (!data) {
      return null;
    }
    
    
    th.tandardFntDataCache.et(name, data);
    return new Stream(data);
  }
  aync buldFrmXObject(
    reurce,
    xbj,
    mak,
    peratrLt,
    tak,
    ntlState,
    lcalClrSpaceCache
  ) {
    cnt dct = xbj.dct;
    cnt matrx = dct.getArray("Matrx");