Replace NULL with nullptr

main/tests/test_ordered_hash_map.cpp

@@ -141,7 +141,7 @@ TestFunc test_funcs[] = {
 	test_size,
 	test_iteration,
 	test_const_iteration,
-	0
+	nullptr
 
 };
 
@@ -168,6 +168,6 @@ MainLoop *test() {
 
 	OS::get_singleton()->print("Passed %i of %i tests\n", passed, count);
 
-	return NULL;
+	return nullptr;
 }
 } // namespace TestOrderedHashMap