Dont search for the sdk on startup in worker mode

pkg/analyzer_cli/lib/src/options.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.options;
 
 import 'dart:io';
 
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:args/args.dart';
@@ skipping 175 matching lines @@
         strongMode = args['strong'],
         lintsAreFatal = args['fatal-lints'];
 
   /// Parse [args] into [CommandLineOptions] describing the specified
   /// analyzer options. In case of a format error, calls [printAndFail], which
   /// by default prints an error message to stderr and exits.
   static CommandLineOptions parse(List<String> args,
       [printAndFail(String msg) = printAndFail]) {
     CommandLineOptions options = _parse(args);
     // Check SDK.
-    {
+    if (!options.buildModePersistentWorker) {
       // Infer if unspecified.
       if (options.dartSdkPath == null) {
         Directory sdkDir = getSdkDir(args);
         if (sdkDir != null) {
           options.dartSdkPath = sdkDir.path;
         }
       }
 
       var sdkPath = options.dartSdkPath;
 
@@ skipping 460 matching lines @@
 
   int _getNextFlagIndex(args, i) {
     for (; i < args.length; ++i) {
       if (args[i].startsWith('--')) {
         return i;
       }
     }
     return i;
   }
 }