Don't set a target library in whole-program mode.

lib/src/run_batch.dart

 // Copyright (c) 2016, 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.md file.
 
 library rasta.run_batch;
 
 import 'dart:async' show
     Future,
     Stream;
 
@@ skipping 62 matching lines @@
         listTests(<Uri>[testDirectory], pattern: options.pattern);
     await for (TestDescription description in tests) {
       count++;
       try {
         Options options = new Options(
             description.uri,
             description.uri.resolve("${description.uri.path}.bart"),
             generateLibrary: this.options.generateLibrary);
 
         ir.Library library = await kernel.loadLibrary(options.input);
-        kernel.processWorkQueue(targetLibrary: options.input);
+        if (this.options.generateLibrary) {
+          kernel.processWorkQueue(targetLibrary: options.input);
+        } else {
+          kernel.processWorkQueue();
+        }
 
         if (options.generateLibrary == true) {
           await openWrite(options.output, (IOSink sink) {
             BinaryPrinter printer = new BinaryPrinter(sink);
             printer.writeLibraryFile(library);
           });
         } else {
           Iterable<ir.Procedure> mainMethods = library.procedures.where(
               (ir.Procedure function) => function.name.name == "main");
 
@@ skipping 44 matching lines @@
 Failures: ${failures.length}
 Average time per test: ${averageTimeMs}ms
 Success rate: ${(100 - failures.length * 100/count).toStringAsFixed(2)}%""");
   }
 }
 
 String padTo(int i, int pad) {
   String result = (" " * pad) + "$i";
   return result.substring(result.length - pad);
 }