[strong] Implement static restrictions on binding/assignment to 'undefined' identifier.

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 4929bbb91e61378427b1763bc469edc7744040e2..6b0118433d2cb7ca40416aa911cb3eedb7a5b3e0 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -569,6 +569,7 @@ class ParserTraits {
   bool IsEval(const AstRawString* identifier) const;
   bool IsArguments(const AstRawString* identifier) const;
   bool IsEvalOrArguments(const AstRawString* identifier) const;
+  bool IsUndefined(const AstRawString* identifier) const;
   V8_INLINE bool IsFutureStrictReserved(const AstRawString* identifier) const;
 
   // Returns true if the expression is of type "this.foo".