Mark tests no longer expected crash

pkg/dev_compiler/test/codegen_test.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 file.
 
 /// Tests code generation.
 ///
 /// Runs Dart Dev Compiler on all input in the `codegen` directory and checks
 /// that the output is what we expected.
 library dev_compiler.test.codegen_test;
 
@@ skipping 368 matching lines @@
       ? uriContent
       : null;
 }
 
 final _crashingTests = new Set<String>.from([
   'language/generic_methods_generic_class_tearoff_test',
   'language/generic_methods_named_parameters_test',
   'language/generic_methods_optional_parameters_test',
   'language/generic_methods_tearoff_specialization_test',
   'language/generic_methods_unused_parameter_test',
-  'language/mixin_illegal_syntax_test_none_multi',
-  'language/mixin_illegal_syntax_test_01_multi',
-  'language/mixin_illegal_syntax_test_02_multi',
-  'language/mixin_illegal_syntax_test_03_multi',
-  'language/mixin_illegal_syntax_test_04_multi',
-  'language/mixin_illegal_syntax_test_05_multi',
-  'language/mixin_illegal_syntax_test_06_multi',
-  'language/mixin_illegal_syntax_test_07_multi',
-  'language/mixin_illegal_syntax_test_08_multi',
-  'language/mixin_illegal_syntax_test_09_multi',
-  'language/mixin_illegal_syntax_test_10_multi',
-  'language/mixin_illegal_syntax_test_11_multi',
-  'language/mixin_illegal_syntax_test_12_multi',
-  'language/mixin_illegal_syntax_test_13_multi',
-  'language/mixin_illegal_syntax_test_14_multi',
 
   // TODO(vsm): Fix these - they import files from a different directory
   // - this triggers an invalid library root build error.
   'lib/html/custom/attribute_changed_callback_test',
   'lib/html/custom/constructor_calls_created_synchronously_test',
   'lib/html/custom/entered_left_view_test',
   'lib/html/custom/js_custom_test',
   'lib/html/custom/mirrors_test',
   'lib/html/custom/regress_194523002_test',
 ]);