FIX: Return if TCP is in STATUS_CONNECTED

If the `StreamPeerTCP` is polled and the TCP connection is `STATUS_CONNECTED` it should return after polling netsocket. Without `return` poll keeps calling `_sock->connect_to_host` and `connect()`.

(cherry picked from commit 61a2f5c534)

core/io/stream_peer_tcp.cpp

@@ -51,6 +51,7 @@ Error StreamPeerTCP::poll() {
 			status = STATUS_ERROR;
 			return err;
 		}
+		return OK;
 	} else if (status != STATUS_CONNECTING) {
 		return OK;
 	}