[JS IR BE] Inline classes lowering

libraries/stdlib/js/irRuntime/core.kt

@@ -108,4 +108,7 @@ internal fun newThrowable(message: String?, cause: Throwable?): Throwable {
     throwable.cause = cause
     throwable.name = "Throwable"
     return throwable
-}
+}
+
+internal fun <T, R> boxIntrinsic(x: T): R = error("Should be lowered")
+internal fun <T, R> unboxIntrinsic(x: T): R = error("Should be lowered")