new classes: special construct stub for derived classs and TDZ for `this`.

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 02f7df64b0d62bbaa9c1eb717ce1db6f8d4939b5..ba1875ca393c27b8e49938b8abbc3b781595ea08 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -2626,7 +2626,7 @@ class FunctionLiteral FINAL : public Expression {
   class HasDuplicateParameters : public BitField<ParameterFlag, 3, 1> {};
   class IsFunction : public BitField<IsFunctionFlag, 4, 1> {};
   class IsParenthesized : public BitField<IsParenthesizedFlag, 5, 1> {};
-  class FunctionKindBits : public BitField<FunctionKind, 6, 4> {};
+  class FunctionKindBits : public BitField<FunctionKind, 6, 5> {};
 };