Deal with unhandled exceptions the same way in all Dart api functions.

runtime/vm/isolate_test.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/assert.h"
 #include "vm/globals.h"
 #include "vm/isolate.h"
 #include "vm/unit_test.h"
 
 namespace dart {
@@ skipping 25 matching lines @@
       "    }\n"
       "    return 0;\n"
       "  }\n"
       "}\n";
   Dart_Handle lib = TestCase::LoadTestScript(kScriptChars, NULL);
   Dart_Handle result = Dart_InvokeStatic(lib,
                                          Dart_NewString("SpawnNewIsolate"),
                                          Dart_NewString("testMain"),
                                          0,
                                          NULL);
-  EXPECT_VALID(result);
-  EXPECT(Dart_ExceptionOccurred(result));
+  EXPECT(Dart_IsError(result));
+  EXPECT(Dart_IsUnhandledException(result));
   Dart_Handle exception_result = Dart_GetException(result);
   EXPECT_VALID(exception_result);
 }
 #endif  // TARGET_ARCH_IA32.
 
 }  // namespace dart