Attach (recommended) or Link to PDF file here:
[jpa2021506744.pdf](https://github.com/mozilla/pdf.js/files/6431655/jpa2021506744.pdf)

Configuration:
- Web browser and its version: Google Chrome v89.0.4389.114 /IE ver 20H2 (OS build 19042.928)/Microsoft Edge 89.0.774.77 (64 bit)
- Operating system and its version: Windows 10 Pro 20H2 19042.928
- PDF.js version: 2.7.570
- Is a browser extension: No

Steps to reproduce the problem:
As you can see from the attached jpa2021506744 [jpa2021506744.pdf](https://github.com/mozilla/pdf.js/files/6431655/jpa2021506744.pdf)  page 15,
When using PDF.js, the  text is cut off on Japanese documents.
What went wrong? I hope to solve this problem.

I tried to improve after seeing these pages.

https://github.com/mozilla/pdf.js/issues/12110
https://github.com/mozilla/pdf.js/pull/13067

Adobe Reader does not have this problem.


What is the expected behavior? (add screenshot)
![jpa_2021_506744_OK](https://user-images.githubusercontent.com/82868736/117239725-473eda80-ae6a-11eb-8de6-1f96250b8351.jpg)

What went wrong? (add screenshot)
![jpa_2021_506744_NG](https://user-images.githubusercontent.com/82868736/117239739-4dcd5200-ae6a-11eb-8db9-61b33088574c.jpg)

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

functn (cmap) {
          f (cmap ntancef IdenttyCMap) {
            return new IdenttyTUncdeMap(0, 0xffff);
          }
          cnt map = new Array(cmap.length);
           Cnvert UTF-16BE
           NOTE: cmap can be a pare array,  ue frEach ntead f
           `fr(;;)` t terate ver all key.
          cmap.frEach(functn (charCde, tken) {
            cnt tr = [];
            fr (let k = 0; k < tken.length; k = 2) {
              cnt w1 = (tken.charCdeAt(k) << 8) | tken.charCdeAt(k  1);
              f ((w1 & 0xf800) !== 0xd800) {
                 w1 < 0xD800 |
                tr.puh(w1);
                cntnue;
              }
              k = 2;
              cnt w2 = (tken.charCdeAt(k) << 8) | tken.charCdeAt(k  1);
              tr.puh(((w1 & 0x3ff) << 10)  (w2 & 0x3ff)  0x10000);
            }
            map[charCde] = Strng.frmCdePnt.apply(Strng, tr);
          });
          return new TUncdeMap(map);
        },
        rean => {
          f (rean ntancef AbrtExceptn) {
            return null;
          }
          f (th.ptn.gnreErrr) {