review: Improve passthrough test in DSLX

Signed-off-by: Robert Winkler <[email protected]>

Author: rw1nkler

xls/examples/passthrough.x

@@ -55,12 +55,13 @@ proc PassthroughTest {
     let tok = send(tok, data_s, data_to_send);
     let (tok, received_data) = recv(tok, data_r);
 
+    trace_fmt!("send: {}, received: {}, in transaction {}",
+      data_to_send, received_data, count + u32:1);
+
     assert_eq(data_to_send, received_data);
-    trace_fmt!("Received and send back {} transactions", count + u32:1);
 
-    if (count == NUMBER_OF_TESTED_TRANSACTIONS - u32:1) {
-      send(tok, terminator, true);
-    } else {()};
+    let do_send = (count == NUMBER_OF_TESTED_TRANSACTIONS - u32:1);
+    send_if(tok, terminator, do_send, true);
 
     count + u32:1
   }