Delete ArrayUtils from codebase (#38251)

Summary:
Pull Request resolved: #38251

I'm deleting ArrayUtils from codebase, this file is not used neither internally or externally (as analyzed in github source)

I believe it's very safe to delete without following any deprecation process

changelog: [Android][Deleted] Delete ArrayUtils from codebase

Reviewed By: christophpurrer

Differential Revision: D47306287

fbshipit-source-id: 1f36ca46db107e21dc55191528cacf6f81cf63ed

Author: mdvacca