Fix unobservable constructor replacement on prototype maps

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 3f568beb4a8f1404aae54804e886aa04c321ac6f..7fd75a2c78e5c4cfe3de09c88a2c127fb1329389 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -11265,13 +11265,15 @@ THREADED_TEST(ObjectGetConstructorName) {
   v8::Isolate* isolate = CcTest::isolate();
   LocalContext context;
   v8::HandleScope scope(isolate);
-  v8_compile("function Parent() {};"
-             "function Child() {};"
-             "Child.prototype = new Parent();"
-             "var outer = { inner: function() { } };"
-             "var p = new Parent();"
-             "var c = new Child();"
-             "var x = new outer.inner();")->Run();
+  v8_compile(
+      "function Parent() {};"
+      "function Child() {};"
+      "Child.prototype = new Parent();"
+      "var outer = { inner: function() { } };"
+      "var p = new Parent();"
+      "var c = new Child();"
+      "var x = new outer.inner();"
+      "var proto = Child.prototype;")->Run();
 
   Local<v8::Value> p = context->Global()->Get(v8_str("p"));
   CHECK(p->IsObject() &&
@@ -11285,6 +11287,11 @@ THREADED_TEST(ObjectGetConstructorName) {
   CHECK(x->IsObject() &&
         x->ToObject(isolate)->GetConstructorName()->Equals(
             v8_str("outer.inner")));
+
+  Local<v8::Value> child_prototype = context->Global()->Get(v8_str("proto"));
+  CHECK(child_prototype->IsObject() &&
+        child_prototype->ToObject(isolate)->GetConstructorName()->Equals(
+            v8_str("Parent")));
 }