base

Fix exception spam in ActivityManagerService.

If a thread that ActivityManagerService should be setting to FIFO dies,
it throws an exception. However, it is expected that threads may
die (due to LMK or app behavior), so we should suppress as much of this
as possible.

bug 30746129

Change-Id: Ief1ab8568fe8b27284ec442570b6a06677998ff1