Add support for attaching observatory to the server

pkg/analysis_server/test/timing/timing_framework.dart

Index: pkg/analysis_server/test/timing/timing_framework.dart
diff --git a/pkg/analysis_server/test/timing/timing_framework.dart b/pkg/analysis_server/test/timing/timing_framework.dart
index cf10ee4e006fca4fd619a3cae903cfe6953e79a6..a71a4f36ce2f71bca6a2d2c4218030b87a9a6b04 100644
--- a/pkg/analysis_server/test/timing/timing_framework.dart
+++ b/pkg/analysis_server/test/timing/timing_framework.dart
@@ -89,8 +89,9 @@ abstract class TimingTest extends IntegrationTestMixin {
     onServerConnected.listen((_) {
       serverConnected.complete();
     });
-    return server.start().then((params) {
-      server.listenToOutput(dispatchNotification);
+    skipShutdown = true;
+    return server.start(dispatchNotification, profileServer: true).then((params) {
+server.listenToOutput(dispatchNotification);
       server.exitCode.then((_) {
         skipShutdown = true;
       });