bug#32825: 27.0.50; Deterministic window management

[martin rudalics]

> 0. emacs -Q
>
> 1. create 3 windows, e.g.:
>     C-x 3
>     C-x 2
>
> 2. type a random letter, e.g. 'z'
>
> 3. eval it with 'C-x C-e'
>     the *Backtrace* buffer with an error appears in some window,
>     quit it with 'q'
>
> 4. eval again exactly with the same key 'C-x C-e',
>     the *Backtrace* buffer appears in another window,
>     not where it appeared the previous time.
>
> What is expected: window management should be more deterministic in the
> sense that the result of the window operation should be expected beforehand,
> not popping windows in random places.

We have 'display-buffer-in-previous-window' for that purpose and the
function responsible for displaying the *Backtrace* buffer should use
it.

martin