neovim always uses encoding=utf8. Thus a lot of utf8 tests are just a
lot of tests. Meanwhile test_regexp_latin.vim is a bit of a lone child,
it can just run as a separate test without a shell layer (running it in
the same process as its utf8 sibling is not allowed
Problem: May redraw when not needed, causing slow scrolling.
Solution: Do not redraw when w_skipcol doesn't change. When w_skipcol
changes only redraw from the top. (issue vim/vim#11559)
f32fb93e43
Co-authored-by: Bram Moolenaar <Bram@vim.org>
