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

Drop down the limit on when we log, since under normal operation we
will never get more than a few K of data due to strict mode.

Try to clean up the code paths coming in and out of binder IPCs to
plug any places where we could disrupt the gather flag of a thread,
causing it to keep gathering stack crawls (which is the thing that
is causing our strict mode data to become so large).

Change-Id: I9a46512283d33e863c429840b465855d1fabb74e