Plumb "enableSuperMixins" option through analysis server (implements DEP 34).

pkg/analysis_server/lib/src/status/get_handler.dart

Index: pkg/analysis_server/lib/src/status/get_handler.dart
diff --git a/pkg/analysis_server/lib/src/status/get_handler.dart b/pkg/analysis_server/lib/src/status/get_handler.dart
index 5b5236c903629ec24f371643f2f74905e5542b43..5412e48b44af60a27ee50a57b36ef883cf6e0d7e 100644
--- a/pkg/analysis_server/lib/src/status/get_handler.dart
+++ b/pkg/analysis_server/lib/src/status/get_handler.dart
@@ -1086,6 +1086,7 @@ class GetHandler {
       _writeOption(buffer, 'Cache size', options.cacheSize);
       _writeOption(
           buffer, 'Enable strict call checks', options.enableStrictCallChecks);
+      _writeOption(buffer, 'Enable super mixins', options.enableSuperMixins);
       _writeOption(buffer, 'Generate hints', options.hint);
       _writeOption(buffer, 'Generate dart2js hints', options.dart2jsHint);
       _writeOption(buffer, 'Generate errors in implicit files',