[es7] Implement async functions parsing

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index a8d0299095cb621cba2dbd3f2aff37ce51e76071..a66bed06d75150e880a19d8644c018e653de6063 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2167,6 +2167,7 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tostring)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_completion)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tolength)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_do_expressions)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_async_await)
 
 
 static void SimpleInstallFunction(Handle<JSObject>& base, const char* name,
@@ -2645,6 +2646,7 @@ bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_tolength_natives[] = {nullptr};
   static const char* harmony_completion_natives[] = {nullptr};
   static const char* harmony_do_expressions_natives[] = {nullptr};
+  static const char* harmony_async_await_natives[] = {nullptr};
 
   for (int i = ExperimentalNatives::GetDebuggerCount();
        i < ExperimentalNatives::GetBuiltinsCount(); i++) {