Cleanup obsolete art apex checks

Module definition of art_apex_boot_integrity is removed in
aosp/I39de908ebe52f06f19781dc024ede619802a3196.

TARGET module com.android.art requires non-existent: art_apex_boot_integrity

This change cleans up remaining references to art_apex_boot_integrity
and removes the source file of art_apex_boot_integrity.

Bug: 7456955
Test: TH; File cleanup. Doesn't affect build.
Change-Id: I61b8f4b09a8f6695975ea1267e5f5c88f64a371f
4 files changed