Add mirrors tests

test/codegen/lib/mirrors/private_symbol_mangling_lib.dart

Index: test/codegen/lib/mirrors/private_symbol_mangling_lib.dart
diff --git a/test/codegen/language/cha_deopt1_lib.dart b/test/codegen/lib/mirrors/private_symbol_mangling_lib.dart
similarity index 62%
copy from test/codegen/language/cha_deopt1_lib.dart
copy to test/codegen/lib/mirrors/private_symbol_mangling_lib.dart
index f49562de496f7f432b7fb2d41dfd5fb60df9091b..8d9c93bb0bd252a8ae0fb1f11282fa0c0763e7ae 100644
--- a/test/codegen/language/cha_deopt1_lib.dart
+++ b/test/codegen/lib/mirrors/private_symbol_mangling_lib.dart
@@ -2,11 +2,13 @@
 // 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 mylib;
+library other;
 
-class T {
+var _privateGlobalField = 3;
 
-  m() => 42;
+_privateGlobalMethod() => 11;
 
+class C2 {
+  var _privateField = 1;
+  _privateMethod() => 3;
 }
-