When recording hour-long traces, logcat messages help
to interpret the trace, giving human readable context on what
is happening on the system.
Furthermore this is particularly helpful for startup
debugging thanks to activity manager instrumentation events
(am_on_create_called, am_on_start, ...).
This is only allowed on userdebug/eng builds.

Bug: 122243384
Change-Id: I4dfaebf21107e9853b0bf42403fbab6c3b4d5141