Try to mitigate issue #31016187: system_server crash in ArraySet.

Instead of crashing, log a wtf and recover.  This is not a problem
in ArraySet, but caused by someone else using an ArraySet without
protecting access to it.  So whoever is calling at this point is
not the cause, and it isn't worthwhile to let them crash.

Change-Id: Iaefa4315b620c9fe24b31507e4aa47a8525c8540