Add API for instrumentations from root to override perms

Similar to how adoptShellPermissionIdentity is used by an
instrumentation started from shell to assume all of the permissions the
shell UID holds, this provides a new API to grant any possible
permission to any UID by an instrumentation that has been started from
root.

Test: WIP test case for this new API  and a random selection of other
        suites that use adoptshellPermissionIdentity.
Fixes: 322381691
Change-Id: Icc7732f72453d4c547428ed95a812f750bb6e9e0