[TEST] Add test checking cast to DNN type

muted temporary due to required support in backends

compiler/testData/codegen/box/casts/castToDefinitelyNotNullType.kt

@@ -0,0 +1,17 @@
+// !LANGUAGE: +DefinitelyNonNullableTypes
+// IGNORE_BACKEND: JVM
+// IGNORE_BACKEND: JVM_IR
+// IGNORE_BACKEND: JS
+// IGNORE_BACKEND: JS_IR
+// IGNORE_BACKEND_FIR: JVM_IR
+
+fun <T> test(t: T) = t as (T & Any)
+
+fun box(): String {
+    try {
+        test<Any?>(null)
+    } catch (ex: NullPointerException) {
+        return "FAIL: expected NPE"
+    }
+    return test("OK")
+}