patch 8.1.1456: WinBar not redrawn after scrolling one line

Problem:    WinBar not redrawn after scrolling one line.
Solution:   Exclude the winbar height when deciding what to redraw.
            (closes #4473)

src/screen.c

@@ -645,7 +645,7 @@ update_screen(int type_arg)
 		type = CLEAR;
 	    FOR_ALL_WINDOWS(wp)
 	    {
-		if (W_WINROW(wp) < msg_scrolled)
+		if (wp->w_winrow < msg_scrolled)
 		{
 		    if (W_WINROW(wp) + wp->w_height > msg_scrolled
 			    && wp->w_redr_type < REDRAW_TOP

src/testdir/test_winbar.vim

@@ -110,3 +110,15 @@ func Test_click_in_other_winbar()
 
   bwipe!
 endfunc
+
+func Test_redraw_after_scroll()
+  new
+  amenu 1.10 WinBar.Next :let g:did_next = 11<CR>
+  redraw
+  call assert_equal("  Next", Screenline(1))
+  echo "some\nmore"
+  redraw
+  call assert_equal("  Next", Screenline(1))
+  bwipe!
+endfunc
+

src/version.c

@@ -767,6 +767,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1456,
 /**/
     1455,
 /**/