More work on issue #17656716: Unhandled exception in Window Manager

Fix Slog.wtf to not acquire the activity manager lock in its code
path, so that it can never deadlock.  This was the original intention
of it, but part was missed.

Now we can put back in the code to detect when strict mode data is
getting large (a little more targeted now to the actual problem),
and use Slog.wtf to report it.  And as a bonus, when this happens
we will now clear all of the collected violations, to avoid getting
in to the bad case where IPCs start failing.  So this should be
good enough for L to fix the problem, with wtf reports for us to
see if the underlying issue is still happening.

Finally, switch a butch of stuff in the system process from Log.wtf
to Slog.wtf, since many of those are deadlocks waiting to happen.

Oh and fix a crash in the settings provider I noticed in APR.

Change-Id: I307d51b7a4db238fd1e5fe2f3f9bf1b9c6f1c041