Tracking task snapshot usage in client process.(3/N)

Track hardware buffer usage within a TaskSnapshot in the client-side
process.
Cache task snapshot objects in TaskSnapshotManager and reuse existing
snapshots based on capture time, to prevent the system server from
always returning a new snapshot object to client if possible.

Flag: com.android.window.flags.reduce_task_snapshot_memory_usage
Bug: 238206323
Test: atest TaskSnapshotControllerTest
Change-Id: I81928a2ff326300441b2aa5030fa3b44f975dc86