Migrate boxWithJava tests to multi-file framework

compiler/testData/codegen/java8/box/dontDelegateToDefaultMethods.kt

@@ -0,0 +1,24 @@
+// FILE: Test.java
+
+interface Test<T> {
+
+    T call();
+
+    default T testDefault(T p) {
+        return p;
+    }
+}
+
+// FILE: main.kt
+
+class Child : Test<String> {
+    override fun call() : String {
+        return "OK"
+    }
+}
+fun box(): String {
+    val res = Child().call()
+    if (res != "OK") return "fail $res"
+
+    return Child().testDefault("OK")
+}