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.
th.handler,
        th._pdfFunctnFactry,
        lcalClrSpaceCache
      );
      cnt patternIR = hadngFll.getIR();
      d = `pattern_${th.dFactry.createObjId()}`;
      lcalShadngPatternCache.et(hadng, d);
      th.handler.end("bj", [d, th.pageIndex, "Pattern", patternIR]);
    }
    return d;
  }
  handleClrN(
    peratrLt,
    fn,
    arg,
    c,
    pattern,
    reurce,
    tak,
    lcalClrSpaceCache,
    lcalTlngPatternCache,
    lcalShadngPatternCache
  ) {
    
    cnt patternName = arg.pp();
    
    f (patternName ntancef Name) {
      cnt rawPattern = pattern.getRaw(patternName.name);
      cnt lcalTlngPattern =
        rawPattern ntancef Ref &&