[K/N][Tests] Adjust moved codegen tests to new infra

^KT-61259

native/native.tests/testData/codegen/function/named.kt

@@ -3,13 +3,11 @@
  * that can be found in the LICENSE file.
  */
 
-package codegen.function.named
-
 import kotlin.test.*
 
 fun foo(a:Int, b:Int) = a - b
 
-@Test fun runTest() {
-  if (foo(b = 24, a = 42) != 18)
-      throw Error()
+fun box(): String {
+    assertEquals(18, foo(b = 24, a = 42))
+    return "OK"
 }