Promote `diagnostic.getDiagnostics()` (#25061).

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 1289 matching lines @@
 ]);
 
 /**
  * ContextData
  *
  * {
  *   "name": String
  *   "explicitFileCount": int
  *   "implicitFileCount": int
  *   "workItemQueueLength": int
- *   "workItemQueueLengthAverage": String
  *   "cacheEntryExceptions": List<String>
  * }
  */
 final Matcher isContextData = new LazyMatcher(() => new MatchesJsonObject(
   "ContextData", {
     "name": isString,
     "explicitFileCount": isInt,
     "implicitFileCount": isInt,
     "workItemQueueLength": isInt,
-    "workItemQueueLengthAverage": isString,
     "cacheEntryExceptions": isListOf(isString)
   }));
 
 /**
  * Element
  *
  * {
  *   "kind": ElementKind
  *   "name": String
  *   "location": optional Location
@@ skipping 1144 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(() => new MatchesJsonObject(
   "rename options", {
     "newName": isString
   }));