patch 8.1.1299: "extends" from 'listchars' is used when 'list' is off

Problem:    "extends" from 'listchars' is used when 'list' is off. (Hiroyuki
            Yoshinaga)
Solution:   Only use the "extends" character when 'list' is on. (Hirohito
            Higashi, closes #4360)
diff --git a/src/screen.c b/src/screen.c
index eb81bee..e56d2bc 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -5594,8 +5594,10 @@
 	    break;
 	}
 
-	/* line continues beyond line end */
-	if (lcs_ext
+	// Show "extends" character from 'listchars' if beyond the line end and
+	// 'list' is set.
+	if (lcs_ext != NUL
+		&& wp->w_p_list
 		&& !wp->w_p_wrap
 #ifdef FEAT_DIFF
 		&& filler_todo <= 0