Add an integration test for kythe support with bug fixes

pkg/analyzer_plugin/test/integration/support/protocol_matchers.dart

 // Copyright (c) 2017, 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 492 matching lines @@
   "TYPE_PARAMETER",
   "UNRESOLVED_INSTANCE_MEMBER_REFERENCE",
   "VALID_STRING_ESCAPE"
 ]);
 
 /**
  * KytheEntry
  *
  * {
  *   "source": KytheVName
- *   "kind": String
- *   "target": KytheVName
+ *   "kind": optional String
+ *   "target": optional KytheVName
  *   "fact": String
- *   "value": List<int>
+ *   "value": optional List<int>
  * }
  */
-final Matcher isKytheEntry =
-    new LazyMatcher(() => new MatchesJsonObject("KytheEntry", {
-          "source": isKytheVName,
-          "kind": isString,
-          "target": isKytheVName,
-          "fact": isString,
-          "value": isListOf(isInt)
-        }));
+final Matcher isKytheEntry = new LazyMatcher(() => new MatchesJsonObject(
+        "KytheEntry", {
+      "source": isKytheVName,
+      "fact": isString
+    }, optionalFields: {
+      "kind": isString,
+      "target": isKytheVName,
+      "value": isListOf(isInt)
+    }));
 
 /**
  * KytheVName
  *
  * {
  *   "signature": String
  *   "corpus": String
  *   "root": String
  *   "path": String
  *   "language": String
@@ skipping 967 matching lines @@
 
 /**
  * rename options
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(
     () => new MatchesJsonObject("rename options", {"newName": isString}));