This change enforces that only system, root or shell may call
getAllPackages(), a hidden API that shares all package names regardless
of user, instant app or package visibility rules.
Bug: 174661955
Change-Id: I77460ae19a4d41151577646441f11e2eddbb741a
Merged-In: I77460ae19a4d41151577646441f11e2eddbb741a
(cherry picked from commit 8124efd57b)