Fix hidden_library2_test.

tests/corelib/hidden_library2_test.dart

Index: tests/corelib/hidden_library2_test.dart
diff --git a/tests/corelib/hidden_library2_test.dart b/tests/corelib/hidden_library2_test.dart
index d47aca72b1f5a85d44827c0cc60845fd0e9cf9c8..6ed52fe05b2d9e29ffcd02472d92df5a28ed9d7e 100644
--- a/tests/corelib/hidden_library2_test.dart
+++ b/tests/corelib/hidden_library2_test.dart
@@ -8,7 +8,7 @@ main() {
   print(['x'].where((_) {
     // We actually don't really care for the successful case. We just want to
     // make sure that the test doesn't crash when it is negative.
-    throw 'fisk';  /// 1: runtime error
+    throw 'fisk';  /// 01: runtime error
     return true;
-  }));
+  }).toList());
 }