Handle symbol literals in closed_world2_test

tests/utils/dummy_compiler_test.dart

Index: tests/utils/dummy_compiler_test.dart
diff --git a/tests/utils/dummy_compiler_test.dart b/tests/utils/dummy_compiler_test.dart
index f1f085797f39261cc5039a53d941887435eab3c3..1252af5e43fe58805b85521da9f107aeefc2a5ec 100644
--- a/tests/utils/dummy_compiler_test.dart
+++ b/tests/utils/dummy_compiler_test.dart
@@ -20,6 +20,8 @@ String libProvider(Uri uri) {
     return buildLibrarySource(DEFAULT_CORE_LIBRARY);
   } else if (uri.path.endsWith('core_patch.dart')) {
     return DEFAULT_PATCH_CORE_SOURCE;
+  } else if (uri.path.endsWith('internal.dart')) {
+    return buildLibrarySource(DEFAULT_INTERNAL_LIBRARY);
   } else if (uri.path.endsWith('interceptors.dart')) {
     return buildLibrarySource(DEFAULT_INTERCEPTORS_LIBRARY);
   } else if (uri.path.endsWith('js_helper.dart')) {