dot: output marked states only for SBA

* src/tgbaalgos/dotty.cc: Do not output marked states if
an automaton has 0 acceptance set (like a monitor).
* src/tgbatest/monitor.test, src/tgbatest/dstar.test: Adjust.

src/tgbaalgos/dotty.cc

@@ -132,8 +132,7 @@ namespace spot
       void print(const const_tgba_digraph_ptr& aut)
       {
 	aut_ = aut;
-	mark_states_ = !opt_force_acc_trans_ &&
-	  (aut_->has_state_based_acc() || aut_->acc().num_sets() == 0);
+	mark_states_ = !opt_force_acc_trans_ && aut_->is_sba();
 	auto si =
 	  std::unique_ptr<scc_info>(opt_scc_ ? new scc_info(aut) : nullptr);
 	start();

src/tgbatest/dstar.test

@@ -63,13 +63,13 @@ digraph G {
   rankdir=LR
   I [label="", style=invis, width=0]
   I -> 0
-  0 [label="0", peripheries=2]
+  0 [label="0"]
   0 -> 0 [label="a & !b"]
   0 -> 1 [label="!a & !b"]
   0 -> 2 [label="b"]
-  1 [label="1", peripheries=2]
+  1 [label="1"]
   1 -> 1 [label="1"]
-  2 [label="2", peripheries=2]
+  2 [label="2"]
   2 -> 2 [label="1"]
 }
 EOF

src/tgbatest/monitor.test

@@ -36,9 +36,9 @@ digraph G {
   rankdir=LR
   I [label="", style=invis, width=0]
   I -> 1
-  0 [label="0", peripheries=2]
+  0 [label="0"]
   0 -> 0 [label="1"]
-  1 [label="1", peripheries=2]
+  1 [label="1"]
   1 -> 0 [label="a"]
 }
 EOF