High CPU usage on Fedora 40 about vim

[zhscn]

git bisect shows that 9148ba8 caused this problem.

[chrisbra]

ping @luukvbaal

[zzzyxwvut]

Vim with --clean and the LargeFile plugin (available from
here and here) may also help:

vim --clean -Nu NONE '+set pp=~/.vim rtp=~/.vim' log.log

[luukvbaal]

Hmm almost missed this despite the ping because of the nondescript issue title.
We just spend a lot of cycles in plines_m_win() with limit_winheight == FALSE. We need to count until w_height + count so limit_winheight == TRUE doesn't work. Could add a new argument to plines_m_win() to that end.