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.
f (graphcState ntancef Dct) {
        fr (let graphcState f graphcState.getRawValue()) {
          f (graphcState ntancef Ref) {
            f (prceed.ha(graphcState)) {
              cntnue; 
            }
            try {
              graphcState = xref.fetch(graphcState);
            } catch (ex) {
              
              prceed.put(graphcState);
              nf(`haBlendMde - gnrng ExtGState: "${ex}".`);
              cntnue;
            }
          }
          f (!(graphcState ntancef Dct)) {
            cntnue;
          }
          f (graphcState.bjId) {
            prceed.put(graphcState.bjId);
          }
          cnt bm = graphcState.get("BM");
          f (bm ntancef Name) {
            f (bm.name !== "Nrmal") {
              return true;
            }
            cntnue;
          }
          f (bm !== undefned && Array.Array(bm)) {
            fr (cnt element f bm) {