Allow shell to create shell_[test_]_data_file sockets.

This makes it easier to write some tests without requiring root for
creating a temporary socket.

Test: m
Test: atest perfetto_integrationtests with https://r.android.com/1575345
      passed with this CL
      failed without with
        avc: denied { create } for name="traced_consumer"
        scontext=u:r:shell:s0 tcontext=u:object_r:shell_data_file:s0
        tclass=sock_file permissive=0

Change-Id: I281778259a55973cda9d6e7af6dea5637591502c
2 files changed