API to query which cores are exclusively assigned.

On devices with cpuset support, the foreground app
may have a core exclusively assigned to it. Add an
API that allows apps to query which core that is,
so it can use that to set scheduling affinity.

Bug: 27381794
Change-Id: Iea148776da6d7abb745ccf9e6ad5ad46491e340a
5 files changed