patch 9.1.1660: popups without decoration are positioned wrong at bottom of screen

patch 9.1.1660: popups without decoration are positioned wrong at bottom of screen

Problem:  Popups without border/padding/title don't flip position when
          cursor is near bottom of screen, while decorated popups do
          flip correctly.
Solution: Use original height instead of truncated height for position
          inversion check, except for info popups to preserve existing
          behavior (glepnir).

fixes: #12546
closes: #18054

Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>