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

^KT-61259

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

@@ -3,8 +3,6 @@
  * that can be found in the LICENSE file.
  */
 
-package codegen.function.sum_foo_bar
-
 import kotlin.test.*
 
 fun foo(a:Int):Int = a
@@ -12,6 +10,7 @@ fun bar(a:Int):Int = a
 
 fun sumFooBar(a:Int, b:Int):Int = foo(a) + bar(b)
 
-@Test fun runTest() {
-    if (sumFooBar(2, 3) != 5) throw Error()
+fun box(): String {
+    assertEquals(5, sumFooBar(2, 3))
+    return "OK"
 }