Bug: 214623625
Put a binder cache in front of ILockSettings#getCredentialType(). The
cache is in LockPatternUtils and the invalidation logic is in
LogSettingsService. The cache is invalidated whenever the
LockSettingsStorage changes.
Three unit tests disable caches because they do not have permission to
write to the system properties.
Test: atest com.android.server.locksettings
Change-Id: Iea4c50ba5cc39de9196d9a9873ae501a946bf9fd
fabb749d64