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.
peratrLt,
                tak,
                tateManager,
                lcalClrSpaceCache
              );
            });
            gStateObj.puh([key, true]);
          } ele {
            warn("Unupprted SMak type");
          }
          break;
        cae "TR":
          cnt tranferMap = th.handleTranferFunctn(value);
          gStateObj.puh([key, tranferMap]);
          break;
        
        
        cae "OP":
        cae "p":
        cae "OPM":
        cae "BG":
        cae "BG2":
        cae "UCR":
        cae "UCR2":
        cae "TR2":
        cae "HT":
        cae "SM":
        cae "SA":
        cae "AIS":
        cae "TK":