[JS IR BE] Reflection support

libraries/stdlib/js/src/kotlin/kotlin.kt

@@ -98,3 +98,5 @@ internal inline fun copyArrayType(from: dynamic, to: dynamic) {
         to.`$type$` = from.`$type$`
     }
 }
+
+internal inline fun jsIsType(obj: dynamic, jsClass: dynamic) = js("Kotlin").isType(obj, jsClass)

libraries/stdlib/js/src/kotlin/reflect/KClassImpl.kt

@@ -60,7 +60,7 @@ internal class SimpleKClassImpl<T : Any>(jClass: JsClass<T>) : KClassImpl<T>(jCl
     override val simpleName: String? = jClass.asDynamic().`$metadata$`?.simpleName.unsafeCast<String?>()
 
     override fun isInstance(value: Any?): Boolean {
-        return js("Kotlin").isType(value, jClass)
+        return jsIsType(value, jClass)
     }
 }