Use exact name lookup for static fields in mirrors.

tests/lib/mirrors/private_class_field_other.dart

Index: tests/lib/mirrors/private_class_field_other.dart
diff --git a/tests/language/export_not_shadowed_by_prefix_helper2.dart b/tests/lib/mirrors/private_class_field_other.dart
similarity index 70%
copy from tests/language/export_not_shadowed_by_prefix_helper2.dart
copy to tests/lib/mirrors/private_class_field_other.dart
index ae2dca5fcf0a4842b29e20d7652b35b6bfd65cfc..85238b6009d14d7ee0a4b500df90e863f8896fa3 100644
--- a/tests/language/export_not_shadowed_by_prefix_helper2.dart
+++ b/tests/lib/mirrors/private_class_field_other.dart
@@ -2,8 +2,8 @@
 // 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.
 
-void f() {
-  f_called = true;
+class C {
+  static var _privateField = 42;
 }
 
-bool f_called = false;
+get privateFieldSymbolInOther => #_privateField;