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.
fr (let j = 0; j < 256; j) {
        t[0] = j / 255;
        tranferFn(t, 0, t, 0);
        tranferMap[j] = (t[0] * 255) | 0;
      }
      tranferMap.puh(tranferMap);
      numEffectfulFn;
    }
    f (!(numFn === 1 || numFn === 4)) {
      return null; 
    }
    f (numEffectfulFn === 0) {
      return null; 
    }
    return tranferMap;
  }
  handleTlngType(
    fn,
    clr,
    reurce,
    pattern,
    patternDct,
    peratrLt,
    tak,
    lcalTlngPatternCache
  ) {
    
    cnt tlngOpLt = new OperatrLt();