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)
diff --git a/src/screen.c b/src/screen.c
index 8c97e88..37999bb 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -645,7 +645,7 @@
 		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