mark the new APIs as experimental

Author: Idan Attias

src/js_native_api.h

@@ -111,10 +111,12 @@ NAPI_EXTERN napi_status napi_create_range_error(napi_env env,
                                                 napi_value code,
                                                 napi_value msg,
                                                 napi_value* result);
+#ifdef NAPI_EXPERIMENTAL
 NAPI_EXTERN napi_status napi_create_syntax_error(napi_env env,
                                                 napi_value code,
                                                 napi_value msg,
                                                 napi_value* result);
+#endif  // NAPI_EXPERIMENTAL
 
 // Methods to get the native napi_value from Primitive type
 NAPI_EXTERN napi_status napi_typeof(napi_env env,
@@ -374,9 +376,11 @@ NAPI_EXTERN napi_status napi_throw_type_error(napi_env env,
 NAPI_EXTERN napi_status napi_throw_range_error(napi_env env,
                                          const char* code,
                                          const char* msg);
+#ifdef NAPI_EXPERIMENTAL
 NAPI_EXTERN napi_status napi_throw_syntax_error(napi_env env,
                                          const char* code,
                                          const char* msg);
+#endif  // NAPI_EXPERIMENTAL
 NAPI_EXTERN napi_status napi_is_error(napi_env env,
                                       napi_value value,
                                       bool* result);