bug#37530: 26.1; Tack characters translated incorrectly

[Eli Zaretskii]

> From: Axel Svensson <mail@axelsvensson.com>
> Date: Fri, 27 Sep 2019 12:37:29 +0200
> Cc: 37530@debbugs.gnu.org
> 
> - GNU Emacs 26.1 started with -Q:
>   The string "⊤⊥⊢⊣" is displayed, which is wrong.
> - Gnome Terminal 3.30.2:
>   The string "⊥⊤⊣⊢" is displayed, as expected.
> - GNU Emacs 26.1 started with -Q -nw under Gnome Terminal 3.30.2:
>   The string "⊥⊤⊣⊢" is displayed, as expected.
> - Chromium 73, with focus in the address bar:
>   The string "⊥⊤⊣⊢" is displayed, as expected.
> - Firefox 60.8.0esr 64-bit, with focus in the address bar:
>   The string "⊥⊤⊣⊢" is displayed, as expected.

Looks like this is due to the list in x-win.el, which starts on line
320 there.  Can someone proofread that list and see if we have other
similar problems?  It looks our data was taken from here:

  https://www.cl.cam.ac.uk/~mgk25/ucs/keysyms.pdf