Allow VrCore to self-grant sensors:high policy

We used to limit self-grant sensors:high by using performanced
API. Now that we need to allow trusted process (i.e. VrCore) to grant
the same schduler policy as we are now moving 6DOF tracking algorithm
into VrCore.

Bug: 78169521
Bug: 110378537
Bug: 110436069
Test: VrCore sensor publishing thread having SchedFifo now
Change-Id: I88fa8763031ae594747b7a5a1938541349919828