BC native tests port to Konan's TestRunner

backend.native/tests/codegen/boxing/boxing0.kt

@@ -1,9 +1,12 @@
+package codegen.boxing.boxing0
+
+import kotlin.test.*
 
 class Box<T>(t: T) {
     var value = t
 }
 
-fun main(args: Array<String>) {
+@Test fun runTest() {
     val box: Box<Int> = Box<Int>(17)
     println(box.value)
 }