vim-patch:9.0.1759: Visual highlight not working with cursor at end of screen line

Problem:  Visual highlight not working with cursor at end of screen line
          and 'showbreak'.
Solution: Only update "vcol_prev" when drawing buffer text.

closes: vim/vim#12865

8fc6a1dae0

test/functional/legacy/display_spec.lua

@@ -9,6 +9,34 @@ local command = helpers.command
 describe('display', function()
   before_each(clear)
 
+  -- oldtest: Test_visual_block_scroll()
+  it('redraws properly after scrolling with matchparen loaded and scrolloff=1', function()
+    local screen = Screen.new(30, 7)
+    screen:attach()
+    screen:set_default_attr_ids({
+      [1] = {bold = true},
+      [2] = {background = Screen.colors.LightGrey},
+    })
+
+    exec([[
+      source $VIMRUNTIME/plugin/matchparen.vim
+      set scrolloff=1
+      call setline(1, ['a', 'b', 'c', 'd', 'e', '', '{', '}', '{', 'f', 'g', '}'])
+      call cursor(5, 1)
+    ]])
+
+    feed('V<c-d><c-d>')
+    screen:expect([[
+      {2:{}                             |
+      {2:}}                             |
+      {2:{}                             |
+      {2:f}                             |
+      ^g                             |
+      }                             |
+      {1:-- VISUAL LINE --}             |
+    ]])
+  end)
+
   -- oldtest: Test_display_scroll_at_topline()
   it('scroll when modified at topline vim-patch:8.2.1488', function()
     local screen = Screen.new(20, 4)