bug#33870: 27.0.50; xref-goto-xref not configurable

[martin rudalics]

> The entire
>
>      (and (not (frame-parameter nil 'unsplittable))
>           (let ((split-height-threshold 0))
>             (setq window (window--try-to-split-window bottom-window alist)))
>           (window--display-buffer buffer window 'window alist))
>
> is bad design.

Removed now from master's 'display-buffer-at-bottom'.

martin