WIP [esnext] implement async iteration proposal

src/interpreter/bytecode-generator.h

Index: src/interpreter/bytecode-generator.h
diff --git a/src/interpreter/bytecode-generator.h b/src/interpreter/bytecode-generator.h
index b9718a3783eee8159788eb17eff945ea870c30f6..d8dbbd86fa3ddea2742f585592b20c9e033cc6b5 100644
--- a/src/interpreter/bytecode-generator.h
+++ b/src/interpreter/bytecode-generator.h
@@ -196,6 +196,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
 
   Handle<Name> home_object_symbol() const { return home_object_symbol_; }
   Handle<Name> iterator_symbol() const { return iterator_symbol_; }
+  Handle<Name> async_iterator_symbol() const { return async_iterator_symbol_; }
   Handle<Name> prototype_string() const { return prototype_string_; }
   Handle<FixedArray> empty_fixed_array() const { return empty_fixed_array_; }
   const AstRawString* undefined_string() const { return undefined_string_; }
@@ -221,6 +222,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
 
   Handle<Name> home_object_symbol_;
   Handle<Name> iterator_symbol_;
+  Handle<Name> async_iterator_symbol_;
   Handle<Name> prototype_string_;
   Handle<FixedArray> empty_fixed_array_;
   const AstRawString* undefined_string_;