Increase the chance of printing a useful error when bootstrapping fails

src/pending-compilation-error-handler.cc

Index: src/pending-compilation-error-handler.cc
diff --git a/src/pending-compilation-error-handler.cc b/src/pending-compilation-error-handler.cc
index 098db62acc31d27ae8fdc98e2a879c1dffa3ee80..10a10320a6e788fac41b920c939149aec651f65b 100644
--- a/src/pending-compilation-error-handler.cc
+++ b/src/pending-compilation-error-handler.cc
@@ -41,6 +41,11 @@ void PendingCompilationErrorHandler::ThrowPendingError(Isolate* isolate,
       break;
   }
 
+  if (!error->IsJSObject()) {
+    isolate->Throw(*error, &location);
+    return;
+  }
+
   Handle<JSObject> jserror = Handle<JSObject>::cast(error);
 
   Handle<Name> key_start_pos = factory->error_start_pos_symbol();