Migrate first block of tests in standalone to standalone_2

tools/migration/bin/migrate_batch.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.
 
 /// Given the beginning and ending file names in a batch, does as much automated
 /// migration and possible and prints out the remaining manual steps required.
 ///
 /// This should be safe to run, and safe to re-run on an in-progress chunk.
 /// However, it has not been thoroughly tested, so run at your own risk.
 
@@ skipping 171 matching lines @@
   }
 
   addFromDirectory("corelib", "corelib_2");
   addFromDirectory("corelib_strong", "corelib_2");
   addFromDirectory("html", "lib_2/html");
   addFromDirectory("isolate", "lib_2/isolate");
   addFromDirectory("language", "language_2");
   addFromDirectory("language_strong", "language_2");
   addFromDirectory("lib", "lib_2");
   addFromDirectory("lib_strong", "lib_2");
+  addFromDirectory("standalone", "standalone_2");
 
   // Include tests that have already been migrated too so we can show what
   // works remains to be done in them.
   const twoDirs = const [
     "corelib_2",
     "lib_2",
     "language_2",
   ];
 
   for (var dir in twoDirs) {
@@ skipping 18 matching lines @@
   }
 
   addStatusFile("corelib");
   addStatusFile("corelib_strong");
   addStatusFile("html");
   addStatusFile("isolate");
   addStatusFile("language");
   addStatusFile("language_strong");
   addStatusFile("lib");
   addStatusFile("lib_strong");
+  addStatusFile("standalone");
   return statusFiles;
 }