Options validation cleanup.

pkg/analyzer/lib/src/task/options.dart

Index: pkg/analyzer/lib/src/task/options.dart
diff --git a/pkg/analyzer/lib/src/task/options.dart b/pkg/analyzer/lib/src/task/options.dart
index a25d146bc89f01e4317f8e229219eec1367c127f..6d066009b5246c63735727e71a2894db9302ce2d 100644
--- a/pkg/analyzer/lib/src/task/options.dart
+++ b/pkg/analyzer/lib/src/task/options.dart
@@ -49,9 +49,6 @@ class AnalyzerOptions {
   static const String enableSuperMixins = 'enableSuperMixins';
   static const String enableTrailingCommas = 'enableTrailingCommas';
 
-  /// This option is deprecated.
-  static const String enableConditionalDirectives =
-      "enableConditionalDirectives";
   static const String errors = 'errors';
   static const String exclude = 'exclude';
   static const String language = 'language';
@@ -83,10 +80,10 @@ class AnalyzerOptions {
   /// Supported `analyzer` language configuration options.
   static const List<String> languageOptions = const [
     enableAsync,
-    enableConditionalDirectives,
     enableGenericMethods,
     enableStrictCallChecks,
-    enableSuperMixins
+    enableSuperMixins,
+    enableTrailingCommas
   ];
 }