Minor aesthetic changes to python file. (#4492)

java/test/src/main/resources/test_cross_language_invocation.py

@@ -1,8 +1,14 @@
 # This file is used by CrossLanguageInvocationTest.java to test cross-language
 # invocation.
-import ray
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
 import six
 
+import ray
+
 
 @ray.remote
 def py_func(value):