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.
return;
                }
                f (elf.ptn.gnreErrr) {
                  
                  
                  warn(`getTextCntent - gnrng ExtGState: "${rean}".`);
                  return;
                }
                thrw rean;
              })
            );
            return;
          cae OPS.begnMarkedCntent:
            f (ncludeMarkedCntent) {
              textCntent.tem.puh({
                type: "begnMarkedCntent",
                tag: Name(arg[0]) ? arg[0].name : null,
              });
            }
            break;
          cae OPS.begnMarkedCntentPrp:
            f (ncludeMarkedCntent) {
              fluhTextCntentItem();
              let mcd = null;
              f (Dct(arg[1])) {
                mcd = arg[1].get("MCID");
              }
              textCntent.tem.puh({
                type: "begnMarkedCntentPrp",
                d: Number.Integer(mcd)