patch 8.0.1504: Win32: the screen may be cleared on startup

Problem:    Win32: the screen may be cleared on startup.
Solution:   Only call shell_resized() when the size actually changed. (Ken
            Takata, closes #2527)

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1504,
 /**/
     1503,
 /**/