Make v8::TryCatch able to consume natively thrown exceptions (again).

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index 304d84ffcf872d6163a19f8a38ce9e7f8df8eaf3..7a72bc2fb2c1e3413d9e9517af554ee0b64aab9e 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -1832,6 +1832,12 @@ v8::TryCatch::~TryCatch() {
     reinterpret_cast<Isolate*>(isolate_)->ThrowException(exc);
     ASSERT(!isolate_->thread_local_top()->rethrowing_message_);
   } else {
+    if (HasCaught() && isolate_->has_scheduled_exception()) {
+      // If an exception was caught but is still scheduled because no API call
+      // promoted it, then it is canceled to prevent it from being propagated.
+      // Note that this will not cancel termination exceptions.
+      isolate_->CancelScheduledExceptionFromTryCatch(this);
+    }
     isolate_->UnregisterTryCatchHandler(this);
     v8::internal::SimulatorStack::UnregisterCTryCatch();
   }