[stubs] Introduce NonPrimitiveToPrimitive builtin.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index 622af22e7f25a72088f9ec17c17a3bbb6ee6cb17..f543381c85baa7b7bd8c86619bc7eb6a39207902 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -784,6 +784,14 @@ inline std::ostream& operator<<(std::ostream& os, TailCallMode mode) {
   return os;
 }
 
+// Valid hints for the abstract operation OrdinaryToPrimitive,
+// implemented according to ES6, section 7.1.1.
+enum class OrdinaryToPrimitiveHint { kNumber, kString };
+
+// Valid hints for the abstract operation ToPrimitive,
+// implemented according to ES6, section 7.1.1.
+enum class ToPrimitiveHint { kDefault, kNumber, kString };
+
 // Defines specifics about arguments object or rest parameter creation.
 enum class CreateArgumentsType : uint8_t {
   kMappedArguments,