patch 9.0.1309: scrolling two lines with even line count and 'scrolloff' set

Problem:    Scrolling two lines with even line count and 'scrolloff' set.
Solution:   Adjust how the topline is computed. (closes #10545)
diff --git a/src/buffer.c b/src/buffer.c
index 0d523bd..8fd81be 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1953,7 +1953,7 @@
     maketitle();
 	// when autocmds didn't change it
     if (curwin->w_topline == 1 && !curwin->w_topline_was_set)
-	scroll_cursor_halfway(FALSE);	// redisplay at correct position
+	scroll_cursor_halfway(FALSE, FALSE);	// redisplay at correct position
 
 #ifdef FEAT_NETBEANS_INTG
     // Send fileOpened event because we've changed buffers.