Poison .arguments and .caller for generator functions

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 1965da104e33106d07fcf2de881f72363c9cddda..435f4084e1a339baec451e0b46b0a6039008c7f7 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -152,6 +152,7 @@ var kMessages = {
   strict_cannot_assign:          ["Cannot assign to read only '", "%0", "' in strict mode"],
   strict_poison_pill:            ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
   strict_caller:                 ["Illegal access to a strict mode caller function."],
+  generator_poison_pill:         ["'caller' and 'arguments' properties may not be accessed on generator functions."],
   unprotected_let:               ["Illegal let declaration in unprotected statement context."],
   unprotected_const:             ["Illegal const declaration in unprotected statement context."],
   cant_prevent_ext_external_array_elements: ["Cannot prevent extension of an object with external array elements"],