Do not hide membership of implementation classes in dart:core.

tests/lib/mirrors/basic_types_in_dart_core_test.dart

Index: tests/lib/mirrors/basic_types_in_dart_core_test.dart
diff --git a/tests/lib/mirrors/basic_types_in_dart_core_test.dart b/tests/lib/mirrors/basic_types_in_dart_core_test.dart
index 2c7602aabf121142a5fe4024ac7be757ac6fd9f2..ef468d76b77fdbbcd42d692a626e6a4a06ca6383 100644
--- a/tests/lib/mirrors/basic_types_in_dart_core_test.dart
+++ b/tests/lib/mirrors/basic_types_in_dart_core_test.dart
@@ -19,9 +19,9 @@ main() {
   Expect.equals(reflectClass(double), cm);
   Expect.equals(#double, cm.simpleName);
 
-  cm = dartcore.classes[#num];  /// 01: ok
-  Expect.equals(reflectClass(num), cm);  /// 01: ok
-  Expect.equals(#num, cm.simpleName);  /// 01: ok
+  cm = dartcore.classes[#num];
+  Expect.equals(reflectClass(num), cm);
+  Expect.equals(#num, cm.simpleName);
 
   cm = dartcore.classes[#bool];
   Expect.equals(reflectClass(bool), cm);