Don't hide interceptors in mirrors.

tests/compiler/dart2js/mirrors_used_test.dart

Index: tests/compiler/dart2js/mirrors_used_test.dart
diff --git a/tests/compiler/dart2js/mirrors_used_test.dart b/tests/compiler/dart2js/mirrors_used_test.dart
index dda883401c200b797ee20fa0d348a71e0ad1949c..ba2afed7e759516e56d85826359a607bb56d076a 100644
--- a/tests/compiler/dart2js/mirrors_used_test.dart
+++ b/tests/compiler/dart2js/mirrors_used_test.dart
@@ -74,6 +74,18 @@ void main() {
     [
         'Foo_staticMethod', // The name of Foo.staticMethod.
         r'instanceMethod$0']; // The name of Foo.instanceMethod.
+
+    // We always include the names of some native classes.
+    List<Element> nativeClasses = [
+          compiler.intClass, compiler.doubleClass, compiler.numClass,
+          compiler.stringClass, compiler.boolClass, compiler.nullClass,
+          compiler.listClass
+        ];
+
+    Iterable<String> nativeNames =
+        nativeClasses.map(compiler.backend.namer.getNameOfClass);
+    expectedNames.addAll(nativeNames);
+
     Set recordedNames = new Set()
         ..addAll(compiler.backend.emitter.recordedMangledNames)
         ..addAll(compiler.backend.emitter.mangledFieldNames.keys)