Add debug support for native compactions

This allows for performing compactions using shell
command which is useful for testing and debugging
compaction locally automated tests to allow compacting
applications not managed by ActivityManager such as
purely native binaries.

Test: am compact native full <pid>
Bug: 267188919
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:5fa297d3c198ed2e93c788b332c3a79ff8efb8d3)
Merged-In: I355bd4c55c96ada392d81cf89381870b9dc79c17
Change-Id: I355bd4c55c96ada392d81cf89381870b9dc79c17