Dont't treat file managers like system

MediaProvider treats system in a special way. Previously, MediaProvider
considered any app that has All Files Access as system. This CL changes
that. However, it makes sure we still treat shell (and root) as system.

Test: atest FuseDaemonHostTest
Test: atest --test-mapping
Fix: 151768142
Change-Id: Id7f769b8e1fe680609b9f034e81c5425806128d1
2 files changed