Add public equals()/hash() methods to PeerHandle. Allows the handle to
be used across multiple calls/sessions.
(cherry-pick of commit 4454bda052aea4087880674bb0e0f81ce2647009)
Bug: 68931709
Test: builds, unit test, integration test
Change-Id: Id06659a640931585893f21b9ee04982d921fe511
Merged-In: I87df50edb948a7afc90e496165013235ddca1e48