Only store user hibernation state in memory when the user is not stopped
and is unlocked since we do not need the information. When a user
unlocks, we get their installed packages and initialize their
hibernation states in memory. When the user is stopped, we clear it.
Bug: 175829330
Test: atest AppHibernationServiceTest
Change-Id: Idb2dba02d53df72daedae0078405634a5db51e8d
89575897ca