JS: prohibit is checks against native interfaces. Warn about casts to native interfaces. Fix #KT-14037, fix #KT-14038

js/js.translator/testData/box/native/castToNativeClassChecked.kt

@@ -0,0 +1,29 @@
+// FILE: castToNativeClassChecked.kt
+@native abstract class S() {
+    abstract fun foo(): String
+}
+
+@native class A(x: String)  {
+    fun foo(): String = noImpl
+}
+
+fun createObject(): Any = A("fail: CCE not thrown")
+
+fun box(): String {
+    try {
+        return (createObject() as S).foo()
+    }
+    catch (e: ClassCastException) {
+        return "OK"
+    }
+}
+
+// FILE: castToNativeClassChecked.js
+function S() {
+}
+function A(x) {
+    this.x = x;
+}
+A.prototype.foo = function() {
+    return this.x;
+}