Add a test that server does not send errors when errors have been disabled

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 9a3b90697a7d875486b9911c9634aeb48c3f4046..a1766e202cb7c8abc106e0c89d5643d62a1e3b26 100644
--- a/pkg/analysis_server/test/integration/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/integration_tests.dart
@@ -643,6 +643,7 @@ class Server {
       bool debugServer: false,
       int diagnosticPort,
       bool enableNewAnalysisDriver: false,
+      bool noErrorNotification: false,
       bool profileServer: false,
       String sdkPath,
       int servicesPort,
@@ -701,6 +702,9 @@ class Server {
     if (!enableNewAnalysisDriver) {
       arguments.add('--disable-new-analysis-driver');
     }
+    if (noErrorNotification) {
+      arguments.add('--no-error-notification');
+    }
 //    print('Launching $serverPath');
 //    print('$dartBinary ${arguments.join(' ')}');
     return Process.start(dartBinary, arguments).then((Process process) {