[esnext] prototype runtime implementation for async functions

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index b236d46a68ac4d85120ec1e1d676d33596758e05..3fa671ac824f2637dff3cfe1a97b85b0a953fdcd 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -336,6 +336,7 @@ static bool IsVisibleInStackTrace(JSFunction* fun,
   if (!FLAG_builtins_in_stack_traces && fun->shared()->IsBuiltin()) {
     return fun->shared()->native();
   }
+
   return true;
 }