Don't reflect ES2015 Function name inference in Function.prototype.toString

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index fc187c4c101f4b094fd95a42829a03e10825ba41..93e00be6bae5e619b0cbf5cc23797ff6955d4bbf 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -900,7 +900,6 @@ class PreParserTraits {
       PreParserIdentifier name, Scanner::Location function_name_location,
       FunctionNameValidity function_name_validity, FunctionKind kind,
       int function_token_position, FunctionLiteral::FunctionType type,
-      FunctionLiteral::ArityRestriction arity_restriction,
       LanguageMode language_mode, bool* ok);
 
   PreParserExpression ParseClassLiteral(PreParserIdentifier name,
@@ -1069,7 +1068,6 @@ class PreParser : public ParserBase<PreParserTraits> {
       Identifier name, Scanner::Location function_name_location,
       FunctionNameValidity function_name_validity, FunctionKind kind,
       int function_token_pos, FunctionLiteral::FunctionType function_type,
-      FunctionLiteral::ArityRestriction arity_restriction,
       LanguageMode language_mode, bool* ok);
   void ParseLazyFunctionLiteralBody(bool* ok,
                                     Scanner::BookmarkScope* bookmark = nullptr);