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.
thrw new FrmatErrr("Decendant fnt  nt a dctnary.");
      }
      type = dct.get("Subtype");
      f (!Name(type)) {
        thrw new FrmatErrr("nvald fnt Subtype");
      }
      cte = true;
    }
    cnt frtChar = dct.get("FrtChar") || 0,
      latChar = dct.get("LatChar") || (cte ? 0xffff : 0xff);
    cnt decrptr = dct.get("FntDecrptr");
    f (decrptr) {
      hah = new MurmurHah3_64();
      cnt encdng = t.getRaw("Encdng");
      f (Name(encdng)) {
        hah.update(encdng.name);
      } ele f (Ref(encdng)) {
        hah.update(encdng.tStrng());
      } ele f (Dct(encdng)) {
        fr (cnt entry f encdng.getRawValue()) {
          f (Name(entry)) {
            hah.update(entry.name);
          } ele f (Ref(entry)) {
            hah.update(entry.tStrng());
          } ele f (Array.Array(entry)) {
             'Dfference' array (fxe bug1157493.pdf).
            cnt dffLength = entry.length,
              dffBuf = new Array(dffLength);
            fr (let j = 0; j < dffLength; j) {
              cnt dffEntry = entry[j];