(TBR) improve integration test failure message

pkg/analysis_server/test/integration/integration_tests.dart

Index: pkg/analysis_server/test/integration/integration_tests.dart
diff --git a/pkg/analysis_server/test/integration/integration_tests.dart b/pkg/analysis_server/test/integration/integration_tests.dart
index 98e986034afaa11068e1f0e18eebd1a70973d1d1..3b7e13af389e84dbc584423085fbacebd435f0b1 100644
--- a/pkg/analysis_server/test/integration/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/integration_tests.dart
@@ -152,7 +152,7 @@ abstract class AbstractAnalysisServerIntegrationTest
     });
     onServerError.listen((ServerErrorParams params) {
       // A server error should never happen during an integration test.
-      fail(params.message);
+      fail('${params.message}\n${params.stackTrace}');
     });
     return server.start().then((_) {
       server.listenToOutput(dispatchNotification);