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 a797272cec2d42432c94e6a7f09ad02c64a9a0f8..f2f573bd6b0d057d0e929067d0e5499fa8549625 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -2619,7 +2619,7 @@ 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> {};
 };