Add an analysis server option to enable null-aware-operator support.

pkg/analysis_server/test/integration/protocol_matchers.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Matchers for data types defined in the analysis server API
@@ skipping 1004 matching lines @@
   "TODO"
 ]);
 
 /**
  * AnalysisOptions
  *
  * {
  *   "enableAsync": optional bool
  *   "enableDeferredLoading": optional bool
  *   "enableEnums": optional bool
+ *   "enableNullAwareOperators": optional bool
  *   "generateDart2jsHints": optional bool
  *   "generateHints": optional bool
  *   "generateLints": optional bool
  * }
  */
 final Matcher isAnalysisOptions = new LazyMatcher(() => new MatchesJsonObject(
   "AnalysisOptions", null, optionalFields: {
     "enableAsync": isBool,
     "enableDeferredLoading": isBool,
     "enableEnums": isBool,
+    "enableNullAwareOperators": isBool,
     "generateDart2jsHints": isBool,
     "generateHints": isBool,
     "generateLints": isBool
   }));
 
 /**
  * AnalysisService
  *
  * enum {
  *   FOLDING
@@ skipping 1138 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(() => new MatchesJsonObject(
   "rename options", {
     "newName": isString
   }));