Add instrumentation data to the analysis server diagnostics page.

pkg/analyzer/test/instrumentation/instrumentation_test.dart

Index: pkg/analyzer/test/instrumentation/instrumentation_test.dart
diff --git a/pkg/analyzer/test/instrumentation/instrumentation_test.dart b/pkg/analyzer/test/instrumentation/instrumentation_test.dart
index 8eff1cf050305e4182f71becf4ced4b8ed0bd1b4..87d6f9bf53177f5573f37f0c71f4288436c78652 100644
--- a/pkg/analyzer/test/instrumentation/instrumentation_test.dart
+++ b/pkg/analyzer/test/instrumentation/instrumentation_test.dart
@@ -166,6 +166,9 @@ class TestInstrumentationServer implements InstrumentationServer {
   String get sessionId => '';
 
   @override
+  String get describe => 'test instrumentation';
+
+  @override
   void log(String message) {
     normalChannel.writeln(message);
   }