Remove policy for deprecated ART apex update scripts

Earlier changes removed the scripts for ART APEX pre- and post-install
hooks (I39de908ebe52f06f19781dc024ede619802a3196) and the associated
boot integrity checks (I61b8f4b09a8f6695975ea1267e5f5c88f64a371f), but
did not cleanup the SELinux policy.

Bug: 7456955
Test: Successful build and boot
Test: adb install com.android.art.debug && adb reboot
Change-Id: I1580dbc1c083438bc251a09994c28107570c48c5
8 files changed