Revert "Add tests for FileUtils.delete and EMPTY_DIREECTORIES_ONLY"

Revert "Add tests for FileUtils.delete and EMPTY_DIREECTORIES_ONLY"

This reverts commit 7aa54967a26cb027fe390ad1c624ebb30f9ac6d5.
The unit test dependend upon the specific order of names that
listFiles() returned members in. The order is completely undefined
and may differ even on different versions of Linux based systems.

A proper unit test for this code would have considered both cases,
where the deletion function was able to remove an empty subdirectory,
or fail to remove a subdirectory because a file was still present
within. This is not such a test.

Change-Id: Ib0a706fea01e4b1ed8c8e859247d247a1279b4bc