Hide Isolate pointer from embedder

runtime/vm/debugger_api_impl_test.cc

Index: runtime/vm/debugger_api_impl_test.cc
diff --git a/runtime/vm/debugger_api_impl_test.cc b/runtime/vm/debugger_api_impl_test.cc
index a516a992e73de2f37e7026c61dac9eb97c574b86..983a1bb30aba54c1122b8c01ee07b4d684ebcded 100644
--- a/runtime/vm/debugger_api_impl_test.cc
+++ b/runtime/vm/debugger_api_impl_test.cc
@@ -1391,7 +1391,7 @@ UNIT_TEST_CASE(Debug_IsolateID) {
 
   Dart_SetIsolateEventHandler(&TestIsolateID);
   Dart_Isolate isolate = TestCase::CreateTestIsolate();
-  ASSERT(isolate != NULL);
+  ASSERT(isolate != ILLEGAL_ISOLATE);
   Dart_EnterScope();
   LoadScript(kScriptChars);
   Dart_Handle retval = Invoke("main");
@@ -1483,7 +1483,7 @@ static void InterruptIsolateRun(uword unused) {
       "}                            \n";
 
   Dart_Isolate isolate = TestCase::CreateTestIsolate();
-  ASSERT(isolate != NULL);
+  ASSERT(isolate != ILLEGAL_ISOLATE);
   Dart_EnterScope();
   LoadScript(kScriptChars);
 
@@ -1517,7 +1517,7 @@ TEST_CASE(Debug_InterruptIsolate) {
   EXPECT(interrupt_isolate_id != ILLEGAL_ISOLATE_ID);
 
   Dart_Isolate isolate = Dart_GetIsolate(interrupt_isolate_id);
-  EXPECT(isolate != NULL);
+  EXPECT(isolate != ILLEGAL_ISOLATE);
   Dart_InterruptIsolate(isolate);
 
   // Wait for the test isolate to be interrupted.