[esnext] prototype runtime implementation for async functions

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 3b8be9b9e0d4b3bd3cf5fbe0505a58d133270d21..f61b84a86fca327ec28a87e5606e47e8bda52ce7 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2392,6 +2392,13 @@ void Bootstrapper::ExportFromRuntime(Isolate* isolate,
           script_is_embedder_debug_script, attribs);
       script_map->AppendDescriptor(&d);
     }
+
+    {
+      SimpleInstallFunction(container, "AsyncFunctionNext",
+                            Builtins::kAsyncFunctionNext, 2, false);
+      SimpleInstallFunction(container, "AsyncFunctionThrow",
+                            Builtins::kAsyncFunctionThrow, 2, false);
+    }
   }
 }
 
@@ -3000,7 +3007,8 @@ bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_exponentiation_operator_natives[] = {nullptr};
   static const char* harmony_string_padding_natives[] = {
       "native harmony-string-padding.js", nullptr};
-  static const char* harmony_async_await_natives[] = {nullptr};
+  static const char* harmony_async_await_natives[] = {
+      "native harmony-async-await.js", nullptr};
 
   for (int i = ExperimentalNatives::GetDebuggerCount();
        i < ExperimentalNatives::GetBuiltinsCount(); i++) {