Remove deprecated ART apex hooks.

Rationale: these hooks were meant for on-device compilation of boot
image combined with fs-verity to protect compilation artifacts. This
approach is now abandoned in favour of on-host compilation of boot
image and packaging it in the apex (to be implemented in a follow-up
patch set).

Bug: b/143761527
Bug: b/125474642

Test: m com.android.art

Test: art/build/apex/runtests.sh: All ART APEX tests passed

Test: Experimental installation of ART apex on device:
  - increase the "version" field in build/apex/manifest-art.json (say,
    to version 5)
  - rebuild ART apex: `m com.android.art`
  - install apex on device:
    `adb install --wait out/target/product/$PRODUCT/system/apex/com.android.art.debug.apex`
    observe the following output in the of the shell command:
      ```
      Performing Streamed Install
      Success
      ```
  - run `adb logcat | grep apexd` in the shell and see that the
    session is staged successfully:
      ```
      [...] apexd   : markStagedSessionReady() received by ApexService, session id <...>
      ```
  - reboot the device with `adb reboot`
  - run `adb logcat | grep apexd` in the shell and see that the
    installation session is completed successfully:
      ```
      apexd   : Successfully activated /data/apex/active/com.android.art@5.apex package_name: com.android.art version: 5
      ```

Change-Id: I39de908ebe52f06f19781dc024ede619802a3196
8 files changed