Enable the new analysis driver by default, use --disable-new-analysis-driver to disable.

pkg/analysis_server/test/stress/utilities/server.dart

Index: pkg/analysis_server/test/stress/utilities/server.dart
diff --git a/pkg/analysis_server/test/stress/utilities/server.dart b/pkg/analysis_server/test/stress/utilities/server.dart
index cc96aca88af5f5aa892ee70b2ba7feb89b65ba3f..88a44ce9a08e44dc3ea026ea51a31eccd91d39f0 100644
--- a/pkg/analysis_server/test/stress/utilities/server.dart
+++ b/pkg/analysis_server/test/stress/utilities/server.dart
@@ -689,8 +689,8 @@ class Server {
     if (useAnalysisHighlight2) {
       arguments.add('--useAnalysisHighlight2');
     }
-    if (enableNewAnalysisDriver) {
-      arguments.add('--enable-new-analysis-driver');
+    if (!enableNewAnalysisDriver) {
+      arguments.add('--disable-new-analysis-driver');
     }
 //    stdout.writeln('Launching $serverPath');
 //    stdout.writeln('$dartBinary ${arguments.join(' ')}');