FileSystemPermissionTest: Expand block device tests.

Ensure that block block devices are not accessible to
non-privileged UIDs / GIDs.

(cherry picked from commit f436e60f186de79aeb1af5dea3b4d9ffa155e221)

Change-Id: I0f3f616daadd6643eb4d4bc4b8abb4693571bea9
1 file changed