patch 9.1.0414: Unable to leave long line with 'smoothscroll' and 'scrolloff'

patch 9.1.0414: Unable to leave long line with 'smoothscroll' and 'scrolloff'

Problem:  Unable to leave long line with 'smoothscroll' and 'scrolloff'.
          Corrupted screen near the end of a long line with 'scrolloff'.
          (Ernie Rael, after 9.1.0280)
Solution: Only correct cursor in case scroll_cursor_bot() was not itself
          called to make the cursor visible. Avoid adjusting for
          'scrolloff' beyond the text line height (Luuk van Baal)

fixes: #14726
closes: #14783

Signed-off-by: Luuk van Baal <luukvbaal@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>