SEPolicy: Changes for new stack dumping scheme.

Applications connect to tombstoned via a unix domain socket and request
an open FD to which they can write their traces. This socket has a new
label (tombstoned_java_trace_socket) and appdomain and system_server are
given permissions to connect and write to it.

Apps no longer need permissions to open files under /data/anr/ and
these permissions will be withdrawn in a future change.

Bug: 32064548
Test: Manual

(cherry picked from commit a8832dabc7f3b7b2381760d2b95f81abf78db709)

(cherry picked from commit 11bfcc1e)

Change-Id: Icc60d227331c8eee70a9389ff1e7e78772f37e6f