ruby: adds size and empty apis to the msg buffer stallmap

src/mem/protocol/RubySlicc_Types.sm

@@ -45,6 +45,8 @@ structure(InPort, external = "yes", primitive="yes") {
   Cycles dequeue();
   void recycle();
   bool isEmpty();
+  bool isStallMapEmpty();
+  int getStallMapSize();
 }
 
 external_type(NodeID, default="0", primitive="yes");

src/mem/ruby/network/MessageBuffer.hh

@@ -123,6 +123,8 @@ class MessageBuffer
 
     void recycle();
     bool isEmpty() const { return m_prio_heap.size() == 0; }
+    bool isStallMapEmpty() { return m_stall_msg_map.size() == 0; }
+    unsigned int getStallMapSize() { return m_stall_msg_map.size(); }
 
     void
     setOrdering(bool order)