Allow shell + priv_app to traverse /data/misc/perfetto-traces

This is a follow-up to r.android.com/1542764.
1. In order to allow priv_app to
   stat(/data/misc/perfetto-traces/bugreport/*) we need
   also the `search` permission to traverse the parent
   directory /data/misc/perfetto-traces.
2. Allow shell to read the new bugreport/ directory.
   shell can read bugreports anyways and this is needed
   for CTS tests.

Bug: 177761174
Bug: 177684571
Test: manual (changpa@)
Change-Id: I39d6a1c7941bcdcdc314a7538c0accfd37c52ca2
2 files changed