Remove forgotten usage of --unparse-validate flag.

tests/compiler/dart2js/unparser_test.dart

 // Copyright (c) 2012, 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.
 
 #import('dart:uri');
 #import('parser_helper.dart');
 #import('mock_compiler.dart');
 #import("../../../lib/compiler/compiler.dart");
 #import("../../../lib/compiler/implementation/leg.dart", prefix:'leg');
 #import("../../../lib/compiler/implementation/dart_backend/dart_backend.dart");
@@ skipping 69 matching lines @@
       Expect.fail('$uri: $begin-$end: $message [$kind]');
     }
   }
 
   compile(
       scriptUri,
       fileUri('libraryRoot'),
       fileUri('packageRoot'),
       provider,
       handler,
-      const ['--output-type=dart', '--unparse-validation']).then(continuation);
+      const ['--output-type=dart']).then(continuation);
 }
 
 testSignedConstants() {
   testUnparse('var x=+42;');
   testUnparse('var x=+.42;');
   testUnparse('var x=-42;');
   testUnparse('var x=-.42;');
   testUnparse('var x=+0;');
   testUnparse('var x=+0.0;');
   testUnparse('var x=+.0;');
@@ skipping 604 matching lines @@
   testFieldTypeOutput();
   testDefaultClassNamePlaceholder();
   testFactoryRename();
   testTypeVariablesAreRenamed();
   testClassTypeArgumentBound();
   testDoubleMains();
   testInterfaceDefaultAnotherLib();
   testStaticAccessIoLib();
   testLocalFunctionPlaceholder();
 }