Clear analyzer caches after each persistent worker build step.

pkg/analyzer_cli/lib/src/build_mode.dart

 // Copyright (c) 2015, 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.
 
 library analyzer_cli.src.build_mode;
 
 import 'dart:core' hide Resource;
 import 'dart:io' as io;
 
 import 'package:analyzer/dart/ast/ast.dart' show CompilationUnit;
@@ skipping 279 matching lines @@
     SyncWorkerConnection connection = new StdSyncWorkerConnection(
         stdinStream: stdinStream, stdoutStream: stdoutStream);
     return new AnalyzerWorkerLoop(connection, dartSdkPath: dartSdkPath);
   }
 
   /**
    * Performs analysis with given [options].
    */
   void analyze(CommandLineOptions options) {
     new BuildMode(options, new AnalysisStats()).analyze();
+    AnalysisEngine.instance.clearCaches();
   }
 
   /**
    * Perform a single loop step.
    */
   WorkResponse performRequest(WorkRequest request) {
     errorBuffer.clear();
     outBuffer.clear();
     try {
       // Add in the dart-sdk argument if `dartSdkPath` is not null, otherwise it
@@ skipping 40 matching lines @@
     String msg = '';
     if (errorBuffer.isNotEmpty) {
       msg += errorBuffer.toString() + '\n';
     }
     if (outBuffer.isNotEmpty) {
       msg += outBuffer.toString() + '\n';
     }
     return msg;
   }
 }