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.
cae "Fnt":
          SleGState = fale;
          prme = prme.then(() => {
            return th.handleSetFnt(
              reurce,
              null,
              value[0],
              peratrLt,
              tak,
              tateManager.tate
            ).then(functn (ladedName) {
              peratrLt.addDependency(ladedName);
              gStateObj.puh([key, [ladedName, value[1]]]);
            });
          });
          break;
        cae "BM":
          gStateObj.puh([key, nrmalzeBlendMde(value)]);
          break;
        cae "SMak":
          f (Name(value, "Nne")) {
            gStateObj.puh([key, fale]);
            break;
          }
          f (Dct(value)) {
            SleGState = fale;
            prme = prme.then(() => {
              return th.handleSMak(
                value,
                reurce,