Check node updates whether the blocks are known (#7568)

* Remove unused ignore_id

src/clientiface.h

@@ -274,6 +274,11 @@ public:
 
 	u32 getSendingCount() const { return m_blocks_sending.size(); }
 
+	bool isBlockSent(v3s16 p) const
+	{
+		return m_blocks_sent.find(p) != m_blocks_sent.end();
+	}
+
 	// Increments timeouts and removes timed-out blocks from list
 	// NOTE: This doesn't fix the server-not-sending-block bug
 	//       because it is related to emerging, not sending.