patch 8.1.0435: cursorline highlight not removed in some situation

Problem:    Cursorline highlight not removed in some situation. (Vitaly
            Yashin)
Solution:   Reset last_cursorline when resetting 'cursorline'. (Christian
            Brabandt, closes #3481)
diff --git a/src/option.c b/src/option.c
index f89c473..19e2b4c 100644
--- a/src/option.c
+++ b/src/option.c
@@ -8306,6 +8306,11 @@
 	p_lrm = !p_lnr;
 #endif
 
+#ifdef FEAT_SYN_HL
+    else if ((int *)varp == &curwin->w_p_cul && !value && old_value)
+	reset_cursorline();
+#endif
+
 #ifdef FEAT_PERSISTENT_UNDO
     /* 'undofile' */
     else if ((int *)varp == &curbuf->b_p_udf || (int *)varp == &p_udf)