spawnUri: fixing test with recent support for multi-script tests.

tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart

Index: tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart
diff --git a/tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart b/tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart
index 9dc8f6d87a742471e02ecb01980e7a3b641fd46a..83c49d7d89de613751fca1ead1b2a69acb3cad85 100644
--- a/tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart
+++ b/tests/isolate/src/APIv2_spawnUriBrowserNegativeTest.dart
@@ -3,6 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.
 
 // Negative test to make sure that we are reaching all assertions.
+// Note: the following comment is used by test.dart to additionally compile the
+// other isolate's code.
+// OtherScripts=APIv2_spawnUriChildIsolate.dart
 #library('spawn_tests');
 #import("../../../client/testing/unittest/unittest.dart");
 #import("dart:dom"); // import added so test.dart can treat this as a webtest.