Migrate boxAgainstJava tests to multi-file framework

compiler/testData/codegen/boxAgainstJava/visibility/protectedStatic/simpleProperty.kt

@@ -1,10 +1,17 @@
-class Derived(): simpleProperty() {
+// FILE: Base.java
+
+public class Base {
+    protected static final String protectedProperty = "OK";
+}
+
+// FILE: 1.kt
+
+class Derived : Base() {
     fun test(): String {
-        return simpleProperty.protectedProperty!!
+        return Base.protectedProperty!!
     }
 }
 
 fun box(): String {
-   return Derived().test()
+    return Derived().test()
 }
-