bug#32825: 27.0.50; Deterministic window management

[Juri Linkov]

> Is that all sufficiently comprehensible and coherent?

Thanks, I tried and everything makes sense.

What values of window-min-height and window-height would you recommend
for the *Backtrace* buffer's window?  Should we set only window-min-height
to e.g. 10 lines tall, or also window-height?  I'd like to see how this
design applies in practice.