Update test.dart for detection output of machine formatted errors

tools/testing/dart/test_progress.dart

Index: tools/testing/dart/test_progress.dart
diff --git a/tools/testing/dart/test_progress.dart b/tools/testing/dart/test_progress.dart
index 6be3a221c2a99ee0f02c9253350e9d9a4559e5e9..63e17b7a7c1f7cb2d9a93b087e4804069668936f 100644
--- a/tools/testing/dart/test_progress.dart
+++ b/tools/testing/dart/test_progress.dart
@@ -124,6 +124,13 @@ class ProgressIndicator {
     }
     output.add(expected.toString());
     output.add('Actual: ${test.output.result}');
+    if (!test.output.diagnostics.isEmpty()) {
+      String prefix = 'diagnostics:';
+      for (var s in test.output.diagnostics) {
+        output.add('$prefix ${s}');
+        prefix = '   ';
+      }      
+    }    
     if (!test.output.stdout.isEmpty()) {
       output.add('');
       output.add('stdout:');