[builtins] Move StringLastIndexOf to a builtin.

src/builtins/builtins.h

Index: src/builtins/builtins.h
diff --git a/src/builtins/builtins.h b/src/builtins/builtins.h
index f86fa6bbb2a7b151af4176e66721613d66e61058..014b4180c8c07e940e8e172a6c3c2d26f04a4add 100644
--- a/src/builtins/builtins.h
+++ b/src/builtins/builtins.h
@@ -535,6 +535,9 @@ namespace internal {
   TFJ(StringPrototypeCharAt, 2)                                               \
   /* ES6 section 21.1.3.2 String.prototype.charCodeAt ( pos ) */              \
   TFJ(StringPrototypeCharCodeAt, 2)                                           \
+  /* ES6 section 21.1.3.9 */                                                  \
+  /* String.prototype.lastIndexOf ( searchString [ , position ] ) */          \
+  CPP(StringPrototypeLastIndexOf)                                             \
   /* ES6 section 21.1.3.10 String.prototype.localeCompare ( that ) */         \
   CPP(StringPrototypeLocaleCompare)                                           \
   /* ES6 section 21.1.3.12 String.prototype.normalize ( [form] ) */           \