DO NOT MERGE ANYWHERE Add test for files in no_backup folder.

Ensures that files put into the getNoBackupFilesDir() is not restored
after doing backup/restore, while files outside the folder are.

Test: make cts -j40 && cts-tradefed run cts -m CtsBackupHostTestCases
Bug: 20088872
Bug: 38492377
Change-Id: Ib7ee6907562051ce4aecae76cefb145315fd6b47
7 files changed