[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 936cf40a3b0aa6c8dac298256f86be6a94811e0a..408915e77a7880107a5b801bbc42bf893a9e74d9 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2370,6 +2370,13 @@ 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);
+    }
   }
 }
 
@@ -2979,7 +2986,8 @@ 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++) {