ExifInterface: Remove dependency on Piex for DNG Test File

This CL removes dependency from Piex for a DNG Test file currently in
ExifInterfaceTest.java.
Specific functions include identifying and setting the byte order of
the data, parsing and saving Exif tags, and retrieving thumbnail
image data and information.
The marker HANDLE_RAW will determine whether to use Piex or not.

Bug: 29409358
Change-Id: I4cd9916ac0c6f294fc44d8b76f52d456aeee8cdc