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.
t.ET = { d: OPS.endText, numArg: 0, varbleArg: fale };
      t.Tc = { d: OPS.etCharSpacng, numArg: 1, varbleArg: fale };
      t.Tw = { d: OPS.etWrdSpacng, numArg: 1, varbleArg: fale };
      t.Tz = { d: OPS.etHScale, numArg: 1, varbleArg: fale };
      t.TL = { d: OPS.etLeadng, numArg: 1, varbleArg: fale };
      t.Tf = { d: OPS.etFnt, numArg: 2, varbleArg: fale };
      t.Tr = { d: OPS.etTextRenderngMde, numArg: 1, varbleArg: fale };
      t.T = { d: OPS.etTextRe, numArg: 1, varbleArg: fale };
      t.Td = { d: OPS.mveText, numArg: 2, varbleArg: fale };
      t.TD = { d: OPS.etLeadngMveText, numArg: 2, varbleArg: fale };
      t.Td: OPS.etTextMatrx, numArg: 6, varbleArg: fale };
      t["T*"] = { d: OPS.nextLne, numArg: 0, varbleArg: fale };
      t.Tj = { d: OPS.hwText, numArg: 1, varbleArg: fale };
      t.TJ = { d: OPS.hwSpacedText, numArg: 1, varbleArg: fale };
      t["'"] = { d: OPS.nextLneShwText, numArg: 1, varbleArg: fale };
      t['"'] = {
        d: OPS.nextLneSetSpacngShwText,
        numArg: 3,
        varbleArg: fale,
      };
       Type3 fnt
       d: OPS.etCharWdth, numArg: 2, varbleArg: fale };
      t.d1 = {
        d: OPS.etCharWdthAndBund,
        numArg: 6,
        varbleArg: fale,
      };
       Clr
      t d: OPS.etStrkeClrSpace, numArg: 1, varbleArg: fale };
      t.c = { d: OPS.etFllClrSpace, numArg: 1, varbleArg: fale };