Fix object pool for lifecycler

The original implementation of object pool for lifecycle
transactions tried to always recycle objects after a
transaction was scheduled. In case when a client was running
in the same process this lead to objects being emptied before
it could actually perform the transaction.
Also when checking if object was already in the pool we should
use "==" instead of equality check.

Bug: 70568084
Bug: 70526039
Bug: 70616950
Test: android.app.servertransaction.ObjectPoolTests
Change-Id: I45eeecc189b9a458d8efdfed256b81cf0baf8b95