WIP [esnext] implement async iteration proposal

src/parsing/parser.h

Index: src/parsing/parser.h
diff --git a/src/parsing/parser.h b/src/parsing/parser.h
index 45ef959ed44644d38db9b75ae6a459bc676f51b9..9b0e1150573fcc0a2029ef7539e955c8ec897afc 100644
--- a/src/parsing/parser.h
+++ b/src/parsing/parser.h
@@ -458,6 +458,9 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
                                       Expression* iterable, Statement* body,
                                       bool finalize,
                                       int next_result_pos = kNoSourcePosition);
+  Statement* InitializeForAwaitOfStatement(
+      ForEachStatement* for_of, Expression* each, Expression* iterable,
+      Statement* body, bool finalize, int next_result_pos = kNoSourcePosition);
   Block* RewriteForVarInLegacy(const ForInfo& for_info);
   void DesugarBindingInForEachStatement(ForInfo* for_info, Block** body_block,
                                         Expression** each_variable, bool* ok);