Update more unit test to new API

src/libsyntax/test_snippet.rs

@@ -57,6 +57,7 @@ fn test_harness(file_text: &str, span_labels: Vec<SpanLabel>, expected_output: &
         let emitter = EmitterWriter::new(Box::new(Shared { data: output.clone() }),
                                         Some(source_map.clone()),
                                         false,
+                                        false,
                                         false);
         let handler = Handler::with_emitter(true, None, Box::new(emitter));
         handler.span_err(msp, "foo");