bug#47234: 28.0.50; frame-inner-height fails without window system on tab-bar-height

[Eli Zaretskii]

> From: "Basil L. Contovounesios" <contovob@tcd.ie>
> Cc: 47234@debbugs.gnu.org,  juri@linkov.net
> Date: Thu, 18 Mar 2021 15:22:48 +0000
> 
> (For example, I don't know when one would pick Ftab_bar_height over the
> frame property tab-bar-lines - maybe the latter can be used
> unconditionally?)

Not AFAIU, because Ftab_bar_height returns its result in pixels, not
in lines.  On TTY frames, each line is 1 pixel.