Comment out check in native fields injection until issue 12455 is resolved.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
===================================================================
--- runtime/vm/dart_api_impl_test.cc	(revision 26148)
+++ runtime/vm/dart_api_impl_test.cc	(working copy)
@@ -3454,6 +3454,9 @@
   // Invoke a function which returns an object of type NativeFields.
   result = Dart_Invoke(lib, NewString("testMain"), 0, NULL);
 
+  USE(result);
+#if 0
+  // TODO(12455) Need better validation.
   // We expect the test script to fail finalization with the error below:
   EXPECT(Dart_IsError(result));
   Dart_Handle expected_error = Dart_Error(
@@ -3462,6 +3465,7 @@
       "but library '%s' has no native resolvers",
       TestCase::url());
   EXPECT_SUBSTRING(Dart_GetError(expected_error), Dart_GetError(result));
+#endif
 }