patch 8.0.1136: W_WIDTH() is always the same

Problem:    W_WIDTH() is always the same.
Solution:   Expand the macro.
diff --git a/src/window.c b/src/window.c
index ca56d9c..a290807 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5777,13 +5777,13 @@
 	     */
 	    wp->w_wrow = line_size;
 	    if (wp->w_wrow >= wp->w_height
-				       && (W_WIDTH(wp) - win_col_off(wp)) > 0)
+				       && (wp->w_width - win_col_off(wp)) > 0)
 	    {
-		wp->w_skipcol += W_WIDTH(wp) - win_col_off(wp);
+		wp->w_skipcol += wp->w_width - win_col_off(wp);
 		--wp->w_wrow;
 		while (wp->w_wrow >= wp->w_height)
 		{
-		    wp->w_skipcol += W_WIDTH(wp) - win_col_off(wp)
+		    wp->w_skipcol += wp->w_width - win_col_off(wp)
 							   + win_col_off2(wp);
 		    --wp->w_wrow;
 		}