Add support for getting the sessionId from instrumentation and sending it to the client

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 48 matching lines @@
  * server.setSubscriptions result
  */
 final Matcher isServerSetSubscriptionsResult = isNull;
 
 /**
  * server.connected params
  *
  * {
  *   "version": String
  *   "pid": int
+ *   "sessionId": optional String
  * }
  */
 final Matcher isServerConnectedParams = new LazyMatcher(() => new MatchesJsonObject(
   "server.connected params", {
     "version": isString,
     "pid": isInt
+  }, optionalFields: {
+    "sessionId": isString
   }));
 
 /**
  * server.error params
  *
  * {
  *   "isFatal": bool
  *   "message": String
  *   "stackTrace": String
  * }
@@ skipping 2396 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(() => new MatchesJsonObject(
   "rename options", {
     "newName": isString
   }));