Switch class loading logic in blackBoxWithJava tests

BoxWithJava tests now by default are loaded with the classloader which has
test's classpath in itself, as in the former ClassPathInTheSameClassLoaderTest

compiler/testData/codegen/boxWithJava/visibility/protectedStatic/funNestedStaticGenericClass.java

@@ -0,0 +1,7 @@
+public class funNestedStaticGenericClass<T> {
+    public static class Inner<S> {
+        protected static String protectedFun() {
+            return "OK";
+        }
+    }
+}