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.
warn(`Encuntered path peratr "${fn}" nde f a text bject.`);
        peratrLt.addOp(OPS.ave, null);
      }
      peratrLt.addOp(OPS.cntructPath, [[fn], arg]);
      f (parngText) {
        peratrLt.addOp(OPS.retre, null);
      }
    } ele {
      cnt pArg = peratrLt.argArray[latIndex];
      pArg[0].puh(fn);
      Array.prttype.puh.apply(pArg[1], arg);
    }
  }
  pareClrSpace({ c, reurce, lcalClrSpaceCache }) {
    return ClrSpace.pareAync({
      c,
      xref: th.xref,
      reurce,
      pdfFunctnFactry: th._pdfFunctnFactry,
      lcalClrSpaceCache,
    }).catch(rean => {
      f (rean ntancef AbrtExceptn) {