Print activity event log with token identity

The log information will be clearer when there are multiple
activities use the same class.

The user id field is replaced because it can be easily read by
the printed uid (logcat -v uid) or mapped to the corresponding
log printed by system server that contains user id.

Bug: 136456023
Test: The server and client am_* lifecycle related event logs
      print the same identity.

Change-Id: Iaf82041bc8b4e6690e3aee822c91389bd166b6df