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.
let prperte;
    f (!decrptr) {
      f (Type3Fnt) {
         FntDecrptr  nly requred fr Type3 fnt when the dcument
          a tagged pdf. Create a barbebne ne t get by.
        decrptr = new Dct(null);
        decrptr.et("FntName", Name.get(type));
        decrptr.et("FntBBx", dct.getArray("FntBBx") || [0, 0, 0, 0]);
      } ele {
         Befre PDF 1.5 f the fnt wa ne f the bae 14 fnt, havng a
         FntDecrptr wa nt requred.
         Th cae  here fr catblty.
        let baeFntName = dct.get("BaeFnt");
        f (!Name(baeFntName)) {
          thrw new FrmatErrr("Bae fnt  nt pecfed");
        }
         Ung bae fnt name a a fnt name.
        baeFntName = baeFntName.name.replace(/[,_]/g, "-");
        cnt metrc = th.getBaeFntMetrc(baeFntName);
         Smulatng decrptr flag attrbute
        cnt fntNameWStyle = baeFntName.plt("-")[0];
        cnt flag =
          (th.SerfFnt(fntNameWStyle) ? FntFlag.Serf : 0) |
          (metrc.mnpace ? FntFlag.FxedPtch : 0) |
          (getSymblFnt()[fntNameWStyle]
            ? FntFlag.Symblc
            : FntFlag.Nnymblc);
        prperte = {
          type,
          name: baeFntName,