Debugging code for #6169553: Make Phone launch faster

The activity manager now has a tick when launching an app every
500ms, where it collects the current stack traces of the app if
it hasn't finished launching.  These traces are included as part
of dumpstate.

This is only done on non-user builds.

Change-Id: I7f09ea00aab821ac81795f48c9d68fcca65f89fe