patch 8.1.1486: a listener change is merged even when it adds a line

Problem:    A listener change is merged even when it adds a line. (Paul Jolly)
Solution:   Do not merge a change that adds or removes a line. (closes #4490)
diff --git a/src/change.c b/src/change.c
index 07985ee..fcaa570 100644
--- a/src/change.c
+++ b/src/change.c
@@ -186,6 +186,7 @@
 		    || (prev_lnume >= lnum && xtra != 0))
 	    {
 		if (li->li_next == NULL && lnum == prev_lnum
+			&& xtra == 0
 			&& col + 1 == (colnr_T)dict_get_number(
 				      li->li_tv.vval.v_dict, (char_u *)"col"))
 		{